Final Design Report

A Sensing Stroller

Prepared for:

1. Our client: Ms. Nancy Cowles,Kids In Danger, Chicago, Illinois

2. DTC Professors:Kathleen Carmichael and Allison Bedell

Date of final presentation: 12/03/2016

Submitted by:

Jaelon Woodard

Jacob Hechter

Annick Nshuti

Bharat Rao

Section 16, Team number 04

Engineering Design and Communication Program McCormick School of Engineering and Applied

Science Northwestern University

Table Of ContentsExecutive Summary 1

Introduction 2

Users and Major Project Requirements 4

Our Approach 5

Formative Research Findings 6

Design Concept and Rationale 8

Limitations and Directions for future development 12

Conclusion 14

Appendices

Appendix A: Project Definition Version 3 15

Appendix B: Background Research 17

Appendix C: Client Interview Guide Summary 20

Appendix D: User Observation Summary 1 24

Appendix E: User Observation Summary 2 26

Appendix F: Mockup Documentation 28

Appendix G: User Testing Summary 1 31

Appendix H: User Testing Summary 2 34

Appendix I: Design Review Summary 37

Appendix J: Project Freeze Documentation 39

Appendix K: Prototype Construction 45

Appendix L: Individual Research | Bharat Rao 49

Appendix M: Individual Research | Jaelon Woodard 57

Appendix N: Individual Research | Annick Nshuti 61

Appendix O: Individual Research | Jacob Hechter 66

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List of Figures

Figure 1: Our Approach 5

Figure 2: The Design Concept 7

Figure 3: Child Checking Circuit 8

Figure 4: Restrain Checking Circuit 9

Figure 5: Tipping Warning Circuit 10

Figure 6: Drawing of Shifting Hand Positions 25

Figure 7: Front View of Mockup Frame 28

Figure 8: Side View of Mockup Frame 28

Figure 9: Top view of the Mockup 28

Figure 10: View of proposed dash board handle 28

Figure 11: View of Steering Reigns 29

Figure 12: View of Back Axle and Wheels 29

Figure 13: View of Back Wheel 29

Figure 14: Front axle and wheels 29

Figure 15: Front and Inside View of Seat 30

Figure 16: Side and outside view of Seat 30

Figure 17: Orthographic View of Overall Structure 41

Figure 18: Isometric Drawing of the overall structure 42

Figure 19: Vibrating Stroller Handle 43

Figure 20: Seat Belt Sensor 43

Figure 21: Toy Steering Wheel 44

Figure 22: Back Wheel 46

Figure 23: Aluminum Rod Attachment 46

Figure 24: Fully Assembled Frame Extension 47

Figure 25: Assembled Toy Steering Wheel 47

Figure 26: Electronics 48

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**Figure 27: Geographical segmentation of market share by percent revenue for baby stroller market

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Figure 28: Basic lightweight umbrella stroller 53

Figure 29: Bugaboo Cameleon 3 Stroller 53

Figure 30 58

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List of Tables

Table 1: Requirements and Specifications 15

Table 2: Major User Observations 1 25

Table 3: Major User Observations 2 27

Table 4: User Testing Results 1 32

Table 5: Design Review Feedback 37

Table 6: Changes Based On Design Review 38

Table 7: Bill of Materials 40

Table 8: Materials for Prototype Construction 45

Table 9: Safety, Ease of Use, Maneuverability Benchmarks of Top Ranked Strollers 52

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Executive Summary

Stroller injuries are well documented, yet they still happen despite the increasing safety measures taken by manufacturers. Children who fall out of strollers are more susceptible to head trauma and bodily bruising than they would be as an adult. Nancy Cowles, our client, came to our DTC team in hopes of finding a solution for this problem. Our team consists of Annick Nshuti, Jacob Hechter, Bharat Rao and Jaelon Woodard and we are team 16-4.

Within the restraint of ten weeks, our team’s design focuses on further decreasing the possibility for injury by implementing electronic warnings, a distracting toy for the child, and a modified skeletal structure for the stroller to prevent tipping.

Electronic Feedback

Our design utilizes an electronic circuit to provide another layer of feedback for the parent when they’re using the stroller. Our stroller causes the handles to vibrate when the seatbelt is not engaged for the child. Additionally, the stroller will emit a warning sound when it is about to tip over. This will not only call the parent into action, but should the stroller be out of eyesight, it will alert a bystander to the danger that’s about to happen to the child and allow them to react before the child is harmed.

Skeletal Structure Alteration

The Sensing Stroller has a widened wheelbase compared to traditional strollers to address the issue of tipping. The modified wheelbase provides greater stability to the stroller by distributing the weight it’s holding over a larger area, making it less likely for the stroller to tip over.

Removable Toy Wheel

There’s a removable toy wheel in front of the child. The wheel provides something to distract the baby, as a bored child is much more likely to accidentally harm themselves than an unoccupied one. Without distraction, the baby is more likely to try to climb out of the stroller when they see something that attracts their attention, thus tipping the stroller over and potentially injuring themselves.

Recount

With these key elements, the stroller fulfills the goal of being safer than a commercial alternative. Our stroller is not the “perfect” design, however, due to our constraints such as money, time, and manufacturing capability. Therefore, our stroller is just one possible solution to this safety issue. We recommend future teams to test and research what structure of a stroller would be the safest to prevent tipping, as well as how best to rectify human error that causes accidents. At some point, the design itself can’t be better, but the way it’s used will make the difference.

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Introduction

From 1990 to 2010, almost 370,000 children five years or younger were diagnosed or treated for some stroller and/or carrier related injury (Fowler, Kobe, Roberts, Collins, & McKenzie, 2016). 370,000 computes to about 17,000 stroller or carrier related injuries per year. Despite of the high maintenance and production standards that are in place by the American Society for Testing and Materials (ASTM) and United States Consumer Product Safety Commission (US CPSC), stroller and carrier related injuries have prevailed, evidenced by the statistics above. Today, strollers and carriers are commonly used products in the United States due to their functionality and efficiency transporting infants from one location to the other. Over the 20 years that stroller and carrier related injuries were studied, from 1990 to 2010, there was a decline proving that the standards are getting stricter and the strollers are being manufactured with the goal of safety as the number one priority. However, there is still a need to address this issue to come closer to eradicating the injuries present due to strollers and carriers.

Hence, Team 16-4 undertook the problem working with Nancy Cowles of Kids in Danger (KID) to design and develop a safer stroller. Ms. Cowles did not have a specific path that she wanted us to take to build a safer stroller; however, she encouraged considerations of different paths and left it up to the team to make the decision regarding the specific age group to target and the type/specifications of the stroller. Over nine weeks in the Fall Quarter of 2016, from September to December, at Northwestern University, Team 16-4 went through the design process to build a stroller to address the safety issue.

Actions have been taken to target the problem. Various manufactured strollers and carriers have integrated safety features. The changes made in the products have been mostly structural, however. The modifications to build safer strollers have all met the standards in place by the ASTM and US CPSC, but unfortunately most products offer multipurpose features that address safety and some other concern instead of focusing solely on safety. For example, Bugaboo designed and produced a stroller with bigger wheels, wider and sturdier base, and overall heavier chassis. The design features Bugaboo chose to integrate highlight an attempt to create a stroller that is less responsive to jittery movements that could injure the baby. There is another motive to Bugaboo’s choice to design a sturdier and bulkier chassis, however. The company, while manufacturing a safer chassis, also went through efforts to make a more aesthetically pleasing stroller. What are now being called “urban assault” strollers, Bugaboo’s bulkier and more rigid product diverges from a typical standard stroller design to appeal to a new brand of consumers. Though Bugaboo aimed at producing a safer stroller, they had ulterior motives for their design choices providing one instance of firms manufacturing strollers that offer multipurpose features not solely focused on safety. Moreover, carelessness on the part of the guardian as well as an adverse environment are reasons for “stroller-related” injuries. Stroller manufacturers have not attempted at designing a stroller that is not only structurally safer, but also targets and mitigates the risk of negligence on the part of the guardian. This is such an important factor in stroller safety, but no company has seemed to notice it. If they have, they have not done anything about it thus far. Alternative solutions were needed to solve this problem.

As stated above, in our research we found that parent negligence was a direct cause of stroller related injuries. We used this research finding to inspire the key modifications and

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features for our redesigned stroller. From this finding, we began the process to come up with possible solutions to solving this negligence problem. Ultimately, of all solutions considered, we found that incorporating sensors would be the safest and most viable. Along with the addition of sensors to our design, we wanted to direct our focus to the structure of the stroller as well. We designed different mockups to represent the changes to our stroller and underwent user testing; user testing provided us with benefits and drawbacks that we had not considered for the modifications we were trying to make. We synthesized all the information we received from user testing, and we combined some features we thought we could integrate into our prototype by addressing the constraints, what each feature offered in terms of solving the safety issue, and the effectiveness of each feature. What emerged was a stroller that consisted of a modified wheel base for stability, sensors to alarm and warn guardians, and a toy steering wheel to keep the infant distracted preventing jostling.

We feel our design addresses the major areas of concern regarding injury in the case study done from 1990 to 2010 because it addresses the problem of parent negligence, and focuses only on the issue of safety. The following report documents the progress our team made in developing the stroller, from the early stages of brainstorming to mock-up testing to design concepts and prototype building. Additionally, highlighted in this report are the niche users we observed and plan to target with our product. Finally, this report concludes with the exact needs that this product meets but also with specific limitations that the stroller has including propositions for future design.

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Users and Major Requirements - JW

Users

Our users consist of guardians, children, stroller manufacturers, standards regulators, and KID. KID’s (Kids in Danger) mission is to promote the development of safer products, advocate for children and educate the public, especially parents and caregivers, about dangerous children’s products. KIDReaches out to parents, caregivers, service providers and others through workshops on dangerous children’s products, media coverage, speaking engagements, social media and web presence and printed materials; Serves as a watchdog on regulatory agencies and manufacturers to assure safe children’s products and advocates for stronger protections for our most vulnerable consumers; Encourages designers and engineers to build safety into each product and promotes the development of the safest products possible for our children.

Because KID is an advocacy group, they don’t have the means to engineer a stroller themselves as a manufacturing company would. Thus, they can only ask and urge companies to think about the safety of children who will be using their products.  In order for our design to be considered successful, our requirements are that the stroller must have latching mechanisms that resist unintentional forces of up to 45 pounds, have no hazardous points or edges, paint and surface coatings, small parts, wood smooth and free of splinters, a parking brake, able to hold a static weight of 100 pounds, not tip over on a 12 degree incline with 40 pounds, and no slippage of restraining straps greater than 1 inch. There are currently voluntary regulations and a proposed bill that would add new regulations to the voluntary standards (ASTM F833).

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Our Approach

Figure 1: Our Approach

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Formative research findings

Observations from the user observations that were conducted at the different user sites, the findings from our research, and our client’s desires are the main things that influenced the way we structured our initial mockups. In fact, our alternative matrices were thought of as a result of three main problems we identified in current strollers.

In addition, expert interviews and mock review helped us gain some more insightful knowledge about the kind of design we wanted to integrated, and this led to the team making new decisions or alternating the approach to solve a particular safety problem in a current stroller.

1.Most accidents happen when parents are away from the strollersThis triggered us to think of introducing a vocal and vision systems that could signal both

a parent that is away or a parent who is using a stroller that chances for an accident happen are too high. (an example of an accident is when is about to tip on either axis, or in front).

Our design is made to solve the problems of parents who are away, in that even if a parent is too away to save the kid, any other person who is near would hear the sounding alarm and be able to save the child. Also, even if the part of saving the accident from happening is completely impossible, at least the baby is immediately followed up right after the accident, hence less chances of perilous accident aftermath.

Since our user and expert interviews thought our design would, to some extent, be solving the safety standards, our team decided to integrate an alerting system for a standard stroller.

2. Tipping over problems in strollersHow can we reduce the chances for a stroller to tip over? Most stroller tipping is a result

of unequal weight distribution in a stroller and the relative position of center of gravity of the stroller system. As a method to approach this, we thought of lowering the center of mass and integrating a larger wheel base for the stroller by using bigger wheels in the back and enlarging the base of the stole.Overall, this will improve on the stability of a current stroller and it will be addressed by integrating a larger wheel base for equal distribution of the weight

3.Lack of easy maneuverability in strollers

Since clearly most parents would not agree that most strollers have easy maneuverability systems, our group’s starting question was “how can we ensure easy maneuverability in a stroller?” In other words, what design can help the use of a stroller that requires the least amount of attention ie, improve on the maneuverability. One way to solve that was integrating a 360- degree freedom front wheel, and putting a rotatable bar.

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Design Concept and Rationale

Overview

The “Sensing Stroller” design that this team has decided contains three major aspects: Electronic Feedback, a removable toy steering wheel for the child to interact with, and modifications to the wheelbase to make it more stable. The feedback serves to warn the parents of two major dangers facing their child, if the seatbelt has become undone and if the stroller is tipping. The removable toy steering wheel is an in place to distract a child to distract it from its surroundings and discourage reaching behavior that may cause the child to fall from the stroller. The wheelbase modifications are to increase its length and width, to provide a longer lever and make it more difficult to tip over.

The following sections describe design of each of the above aspects, and the reasoning for their addition

Figure 2: The Design Concept

Electronic Feedback System

The electronic feedback assembly consists of 6 major parts (See Appendix J): An Arduino or similar small computational device, mounted on the back of the stroller A Reed Sensor with a magnet, mounted on both portions of the stroller restraint clip One or more vibrating motors, mounted on the handle of the stroller A limit switch mounted on the stroller seat A speaker, mounted next to the Arduino An at least 2 axis gyroscope and accelerometer. In this case, it is already integrated into

the Arduino

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There are three main functions of the assembly: To check if there is a child in the stroller To warn the user if the stroller harness isn’t engaged To warn the user if it is tipping

The assembly to check if a child is in the stroller consists of the Arduino and the limit switch. The limit switch is placed inside the seat, so that the weight of the child presses down on it and completes a circuit to give signal. The purpose of this assembly is to conserve resources, as we don’t want to be consuming battery power or processing power when the child is in the seat. Both other functions are conditional upon the child being in the seat.

Figure 3: Child Checking Circuit

Stroller Harness Assembly

The assembly to warn the user if the stroller harness isn’t engaged consists of a reed sensor, a vibrating motor, and the Arduino. A reed sensor is basically a magnetic sensor, and when a magnet is brought near, it completes the circuit. In this case, the reed sensor would be attached to one side of the harness buckle, and the magnet is attached to the other. If the harness is engaged, the circuit is complete, and the Arduino receives a signal. However, if the harness is not engaged, the circuit is not complete, and the Arduino gets no signal. If the Arduino doesn’t get the signal, then the Arduino sends power to the vibrating motor in the handle, and the parents receives a relatively quiet but very noticeable signal the harness is not in use.

Falls from strollers make up 66.8% of stroller injuries (Appendix B). A significant portion of that can be attributed to the seat belt not being fastened by the parent or being defeated by the child in the stroller (Appendix O). The rationale behind this assembly is that by letting users know that the harness is not in use will remind them to engage the restraints, thusly reducing the rates of restrain non-use, as well as to notice when their child has defeated the restraints.

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Figure 4: Restrain Checking Circuit

Tipping Alarm

The assembly to warn the user if the stroller is tipping. It consists of a gyroscope, a speaker, and the Arduino. Using the gyroscope, the Arduino keeps track of its orientation compared to its starting position, storing it as the initial pitch, yaw, and roll values. Should the difference between the original yaw or roll values and the current yaw or roll values become too high, it will be the indication that the stroller is in the process of tipping. When this occurs, the Arduino will send a signal to the speaker, which will generate a loud alarm, to grab the attention of the user and other nearby people.

The rationale for this assembly is that any sort of attention grabbing warning for a stroller tipping would give a user a better chance to respond to intervene and stop the stroller from tipping. Stroller tipping accounts for 15.5% percent of total stroller injuries, and this assembly gives the opportunity to intervene and stop some of these incidents. Even if the parents are usable to prevent tipping, they still are more aware of the situation, and able to respond to any injury in a timelier manner than without the alarm.

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Figure 5: Tipping Warning Circuit

Toy Removable Steering Wheel

The removable steering wheel is a free spinning steering wheel within arm’s reach of the child occupying the stroller. It is attached to a bent rod, which is attached further down the stroller seat. This rod can be easily detached from the stroller by the parent to prevent obstruction due to the steering wheel (figure 12 and 13). The steering wheel itself is a “Baby And Toddler Car Driver With Driving Tunes - Take Along Toy” (Table 7).

The rational for this design is how children behave when they are in the stroller. Oftentimes, when they see something particularly interesting, they attempt to interact with it by reaching out and attempting to grasp it. This can cause causing them to fall out when they unbalance themselves. This is especially common when the stroller is stopped, so the purpose of the steering wheel is to provide entertainment while in the stroller and reduce dangerous behaviors (Appendix O).

Widened Wheel Base

For the purposes of widening the wheel base, the back wheels of the stroller will be moved backwards 12 inches and, the distance between the wheels will be increased an additional 3 inches, 1.5 on each side. This, along with the removal of any existing back axel in the base will provide a widened back wheel base and an area where it remains comfortable to move and the user won’t accidentally kick the stroller.

The reason for this modification is to increase the stability of the stroller and prevent tipping. As stated earlier, stroller tipping accounts for 15.5% percent of total stroller injuries, and that number can be decreased if the strollers wheel base is widened, increasing the amount of torque and force required to cause the stroller to tip. The reasoning for the specific numbers above is that in our prototype, those length and width increases move the wheels to just under the

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outside edges of the stroller handle. This is the limit of the wheel base size where it still remains comfortable to push and steer.

Rationale Summary

The major purpose of all three modifications is to prevent or mitigate two major sources of injury, falls from stroller because the seat belt was not fastened and the stroller tipping over. Falls from strollers make up 66.8% of stroller injuries (Appendix B). A significant portion of that can be attributed to the seat belt not being fastened by the parent or being defeated by the child in the stroller. Another reason for these falls is reaching behavior that children engage in when attempting to interacting with their environment, causing them to fall out when they unbalance themselves. This is especially common when the stroller is stopped, so the purpose of the steering wheel is to provide entertainment while in the stroller and reduce dangerous behaviors (Appendix O). Strollers tipping also makes up 15.5% of the remaining total injuries, so widening the stroller base to increase stability and adding a warning for stroller tipping exist to reduce incidence and severity of these incidences.

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Directions for Future Development

Introduction

Team 16-4, under the specific constraints of time interval and location, designed a stroller that targeted the problem of stroller related injuries with a concentration on guardian negligence and carelessness. Additionally, we decided to devise a solution for distracting the baby so that they would not jostle around too much in the stroller causing tipping. Some of the designs we chose to implement could be taken further granted more time, so below are the propositions for future development to build upon the current designs that are in place in our stroller.

Structure: ● The expansion and extension of the wheel base provided great stability to the

stroller and did its job in preventing tipping. However, we found that the hinges connecting the large back wheels to the main chassis of the stroller were quite loose. The weight of the back wheels put immense tension on the hinges, which is what caused them to loosen over time. Under our time constraints, we were forced to settle with a large, stabilizing, and loose wheel base in place behind the chassis. An idea for development for future teams could possibly be to devise a way to maintain the stability of the stroller given the large extended wheel base while also keeping the hinges tightly in place.

● We think the toy steering wheel was a great addition to the stroller as it indirectly prevented stroller injury while keeping the baby occupied and happy. Given more time though, we would have liked to rubberize the aluminum parts that connect the steering wheel to the chassis of the stroller. The aluminum sticks out like a sore thumb in terms of the unity of the design giving the stroller a very cold look. Because the rest of the stroller’s chassis is coated with black foam, we would have liked to coat the aluminum apparatus of the toy steering wheel with black foam as well. A proposition for future teams would be to incorporate a more aesthetically pleasing apparatus for the toy steering wheel – one that hides the aluminum and maintains design unity.

● When the time came to decide the features we wanted to implement into the stroller, we chose sensors, a widened wheel base, and a toy steering wheel. These three features were all chosen over modified steering, specifically using a handle or wheel. We wished we could have incorporated one handed steering into our design. Though it may incline guardians to multitask while pushing the stroller, we thought it would enhance the maneuverability of the stroller. After all, pushing a stroller that is meant to be pushed with one hand is safer and more efficient than pushing a stroller that is not meant to be pushed with one hand. Unfortunately, we decided to leave this feature out given the complexity of the concept and the time constraints we were under; however, undertaking and implementing this concept would be extremely beneficial in the long run for designing a stroller that satisfies multiple use cases.

Seat: ● Early in the design process, our team had the intention of modifying the seat to

increase the comfortability for the infant. We did not end up going this route, but

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we think it is imperative that the seat be considered to increase comfort and safety. We chose to retrofit a stroller that had a seat with a small area for the infant’s buttocks. Due to our time constraints, though, we decided to only focus on the sensors, toy steering wheel, and expanded wheel base using a previously designed stroller. If given more time, we would have liked to consider the right-sized seat as well as material to make the baby more comfortable, discouraging them from moving around too much, which in turn would prevent safety hazards. Future design teams could consider a modified seat as an extended solution to solving the safety issue. Moreover, consideration of building a completely new chassis from scratch would be a solution to expanding the area of the seat for the infant’s buttocks.

● Memory foam seating is one design feature we were thinking about implementing. Because of its design and properties, we decided not to go this route and scrap building a new seat all together. Research into materials like that of memory foam but with different energy properties could further the development of a safer and more comfortable seat.

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Conclusion - JW

As a team, we feel as if we’ve accomplished our goals of minimizing tipping risk, and helping to minimize accidental user error. The sensing stroller is sturdy due to the wheelbase modification, it helps keep the child from getting themselves into danger with the steering wheel, and provides extra layers of warning for impending danger with the electronic sensors. With the limitations of time and money, there are a few areas we’d like to improve upon if the circumstances were different. The stroller is safe, but it’s maneuverability is limited and makes the stroller feel bulky. We’d also like more time to tinker with the electronic capabilities of the stroller, as it’s an area that could provide the stroller with even more safety capabilities. These are the two main areas we would suggest future teams to focus on with more resources and manufacturing capabilities.

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Appendix A: Project Definition Version 3 Project Name: Safer Stroller ProjectClient: Nancy Cowles/Kids in Danger (KID)Team Members: Annick Nshuti, Jaelon Woodard, Jacob Hechter, Bharat RaoDate: 11/14/2016

Mission Statement: To design stroller add-ons which reduce the commonality of children falling from strollers, and reduce the commonality of strollers tipping while children are in the strollers.

Project Deliverables: A conceptual model of the above stroller modifications prototype stroller containing these modifications. The conceptual model may take the form of sketches or other visual media to demonstrate the function.

Constraints:● Time limit within the quarter - approximately 11-12 weeks total● 100-dollar budget - materials/mock-ups● Not enough time to find or meet experts

Users/Stakeholders:● Parents, relatives, or other guardians who will be using the stroller● Experts and Users around campus● Children who will be transported in the stroller● Kids In Danger, who will advocate for the adoption of greater stroller safety.● Stroller companies, who would be theoretically manufacturing and selling the strollers

Table 1: Requirements and Specifications

Requirements Specifications

Reduce Likelihood of Tipping ● Larger overall wheel base● Lower center of● Incorporate an electronic Auditory feedback in

potential tipping situations

Reduce likelihood of Falling from stroller ● Entertainment Device to prevent dangerous child

behaviors like reaching outside of the stroller● Incorporate electronic feedback to warn of seat

belt being disengaged.

Consumer Benefits● Storage space ● Area for parents to store other things they carried

with them● Easy to access Arduino to change batteries

Cost● Minimize consumer cost ● Use lowest cost sensors and electronics that can be

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used, or items available in the shop● Construction of stroller done in inexpensive

locations (The Shop)

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Appendix B: Background Research 1Date(s): 9/21/2016 - 9/23/2016Time(s): 5:00 - 5:30 PMLocation(s): Lisa’s Cafe, Ford Design Building G211Key People In Attendance: Jacob Hechter, Annick Nshuti, Jaelon Woodard, Bharat Rao

Methods:Currently, our research methods consists solely of research from academic sources and other online resources, as well as information gained from a client interview.

Findings:● Injuries

○ Contact of injury■ Overwhelmingly the result of contact with the ground (78.7%)■ Second largest cause was the result of contact with the stroller itself

(14.2%)○ Cause of injury

■ Large portions of injuries occurred as a result of a fall from a stroller (66.8%)

■ Second largest portion of injuries occurred because the stroller tipped over (15.5%)

○ Demographics of Injury■ 43.0% younger than 1 year■ 34.7% between 1 and 2 years of age

● Reason for this high amount in a 0 to 5-year-old age range is the increased usage of strollers for children under the age of two compared to those older than 2

■ Slight Male Bias - 53%-47%● This kind of bias appears with most/all child related products (Mrs.

Cowles)○ Nature of the Injury

■ The head (43.0%) and face (31.0%) were most commonly injured the most injured part of the child

■ The most common diagnoses were soft tissue injuries (39.4%) and traumatic brain injuries/concussions (24.6%)

■ Note: the reporting methodology recorded the most severe injury under injury type, and those labeled under head and face could have had other serious injuries on other parts of their bodies

■ On average, one child dies each year from stroller-related injuries according to data from 2007-2009. Many of these deaths occur when babies are left to sleep with the stroller’s back rest in the reclined position. They may slip feet-first through a leg opening until their head is trapped and they are strangled — at least 5 deaths are associated with this hazard. (“Product Hazards - Strollers | Kids In Danger,” n.d.)

○ (Fowler, Kobe, Roberts, Collins, & McKenzie, 2016)○ When do these injuries occur?

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■ Research says the stroller usually is tipped over or the baby slides down and out of their restraints in the stroller.

■ Not locking the wheels on the stroller is a common cause for why strollers tip over when supporting weight or a child. (“Falls From Strollers And Baby Carriers Can Cause Serious Injuries,” n.d.)

■ (Rettner, 17, & ET, n.d.)● Stroller Design and Specifications

○ Height: ~40”○ Width: 20”-25”○ Depth/Length: 18” - 27”○ Usually foldable○ 3 or 4 wheeled

■ 4 wheels are more stable○ Plastic, Steel, or Aluminum frames○ Cloth or canvas seating○ Some have detachable car seats○ Ranges derived from (“Featured Products - Graco,” n.d.)

● Standards for Strollers○ Strollers must adhere to ASTM F833, which is a set of tests and specifications in

order to be deemed safe for public use.○ Standards range from physical tests to design specifications such as having no

sharp edges. (“Federal Register Notices | CPSC.gov,” n.d.)● Types of Strollers

○ Standard size: decent amount of storage, 16-37 pounds, most come with a car seat adapter, almost flat fully reclined seat

○ Car seat frame stroller: Less expensive, weighs less than standard size (6-11 pounds), and also clicks right into the stroller or car.

○ Lightweight: Usually made of canvas. The canvas provides the ease of allowing the stroller to fold up and fit almost wherever (compact). No car seat adapter → used for babies >6 months. Smaller wheels which is more dangerous, less maneuverable, and hard to push on rough surfaces.

○ Jogging: Large, air filled wheels. Can be rolled smoothly and straight while on a jog or walk. No car seat adapter. Not compact. 23-31 pounds. Shock absorbers.

○ Double: Stroller designed for two babies. Usually for twins. Weighs between 21-36 pounds. Bassinet included with most.

Implications:● Should we actually build a stroller, the 4 wheeled, more stable design would be preferred.● A large portion of the injuries occur because of falls from the stroller, and subsequent

contact with the ground, making the secure fastening of the child in the stroller a high priority target for improvement

● The head and face seem to be the most commonly injured, which would indicate another high priority focus area, to attempt to protect the head.

● The most common cause of death seems to be resulting from strangulation in the harness, which would be another highly important focus area

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References

Falls From Strollers And Baby Carriers Can Cause Serious Injuries. (n.d.). Retrieved October 5, 2016, from http://www.npr.org/sections/health-shots/2016/08/18/490468692/falls-from-strollers-and-baby-carriers-can-cause-serious-injuries

Featured Products - Graco. (n.d.). Retrieved November 15, 2016, from http://www.gracobaby.com/products/pages/featuredproducts.aspx

Federal Register Notices | CPSC.gov. (n.d.). Retrieved November 15, 2016, from https://www.cpsc.gov/Regulations-Laws--Standards/Federal-Register-Notices/2013/Safety-Standard-for-Carriages-and-Strollers/#h-20

Product Hazards - Strollers | Kids In Danger. (n.d.). Retrieved from http://www.kidsindanger.org/product-hazards/strollers/

Rettner, R., 17, S. W. | A., & ET, 2016 12:01am. (n.d.). Serious Head Injuries from Baby Strollers on the Rise. Retrieved November 15, 2016, from http://www.livescience.com/55785-stroller-injuries-children.html

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Appendix C: Client Interview Guide and SummaryDate: 9/26/2016Time: 5:00 - 5:30 PMLocation: Ford Design Building G211Key People In Attendance: Prof. Carmichael, Prof. Bedell, Jacob Hechter, Annick Nshuti, Jaelon Woodard, Bharat Rao, other DTC teams, Nancy Cowles (Telepresence)Conditions of Environment: Interview through Skype

Mission of Kids In Danger

The primary mission of KID is as an advocacy and awareness group centered around infants and consumer products commonly used by infants, or by parents of infants. They provide awareness about recalls and provide advocacy for those hurt by faulty strollers, as well as work with lawmakers and manufacturers on stroller standards. Their mission is to reduce injury to young children.

Information/Notes● Biggest threat to kids in strollers?

○ Threat to children is commonly due to falls, in any product○ Some of these injuries occur because of inadequate securing of the latch the

parent wasn’t aware of○ Finger pinching, amputation○ Wheels○ Brakes○ Openings can be dangerous - the child becoming entrapped and getting strangled

■ Getting fingers caught in small opening● Want something that is easy to use, that parents don’t have to think about

○ A harness seems to be what she’s looking for● Common inconvenience? Don’t look at all the warnings (information overload)

○ Use intuitively, and the warnings should be either visual or audio● Sometimes just leave the child at home because “it's at home and it's safe”● Think the mandatory standard is pretty strong● Second hand strollers? Not as “sharp” or possibly recalled and people don’t always know

what’s recalled○ As long as it’s safe and not recalled○ Old products don’t meet current standards○ More beat up, wear and tear

● One stroller for the baby’s early years?○ Parents often don’t know that infants and older children need different types of

strollers, leading to more likely restraint related injuries.● Variety is good but it’s mostly up to our discretion as long as the problem is solved● What would you consider success?

○ A prototype that addresses the hazards and could pass safety testing in its final phase

○ Is it marketable?● Foreign made strollers?

○ Most brands made in foreign countries?

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○ The manufacturer's responsibility to know the safety standards and abide by them.○ As long as it’s the same quality, most parents don’t know whether or not brands

are American made● Parents often blame themselves for their children’s injuries, even with faulty products● Injuries are underreported as not everyone goes straight to the emergency room rather

than urgent care● Common for babies to wear safety gear like a helmet?

○ Most don’t but there are helmets available for special needs children○ Most parents don’t want to try to get their parents to wear helmets as it’s a hassle.

● Complaints about strollers that aren’t injury related?○ Easy to fold○ Get children in and out○ Weight of the stroller○ Does the car seat fit well?

● Specific model that’s best for safety and ease of use?○ No, as cost doesn’t always guarantee top of the line safety○ Being hard to use means less likely to be bought

● Males generally more likely to be injured?○ Across all infant product injury patterns, not just stroller

● Parents aren’t going to buy it because it's safe, that's just an assumption they make○ Parents think about comfort a lot, but they don’t really know what is comfortable

for babies other than from how they behave○ Appearance: It looks cool/it looks safe

● Going to get a list of child care centers who are willing to help● Previous problems engineering groups have had

○ User input is important○ Parents with young children, individual meetings are going to take some time○ Big groups are other things you could look at (go to toys are us or to the park and

watch or ask)● Good idea to focus on a single stroller OR good idea to make it so it forces the user to

buy a new stroller● Safety.gov “yelp page”● Time to set up latch is a big factor

PerspectiveUsers: It is important to note a clear distinction between injury due to a faulty stroller andinjury due to the misinformed or unaware parents/guardians. The overall opinion of the team after the interview with Ms. Cowles is that there is a gray area in how some of the babies/infants actually get injured. Further research will allow us to enhance our understanding of this distinction, which right now is not very clear to us. Certain statistics have been made available that give us information about the injuries solely caused by a faulty stroller; however, there are scenarios in which the injury could be caused by a combination of both a faulty stroller and an unaware parent or guardian. These scenarios could be categorized under one specific cause when the injury and situation is really not that simple.Competition/Market: Ms. Cowles was informative about the feature details of general strollers. However, the perspective of the group is that there is still much to be researched

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and discussed about the overall stroller market. The competitive nature of the market, especially today, is one reason certain companies tend to cut corners: companies want to rush a product to market in order to compete with a rival product, or they have a misunderstanding of specifications that the product must meet. Additional information about specific stroller brands and their histories detailing manufacturing and marketing could be useful in determining how and why certain faulty strollers end up penetrating the market.Conditions of Use: Under various circumstances, babies and even parents/guardians will choose to operate the stroller in different ways. Our group would like to search for these varying conditions of uses, which could vary for a number of reasons: a different stroller brand, lax parenting, or a generally uncomfortable baby. Comfort is also subjective. A stroller that enters the market could be found comfortable by one infant but not by another. The question is if this is the fault of the manufacturer or the user’s problem. These questions we hope will be answered in the user scenarios.

Client Preferences:Ease of use: our client makes it clear that the product she prefers is the one that easy to use and preferably does not require the parents to think about the procedures of use. The steps and the time it takes to set up the latch are crucial. She is also interested in a product that not only passes the safety test but also involves additional safety features. In this case our client seems to be interested in features like a harnessGetting rid of unsafe or faulty features like open holes and making sure that the product has an adequately secure latch is another preference mentioned by our client.Last but not least, our client is interest in a product that is marketable, that is a fit for good demand and the one that addresses the hazards.

Unanswered/New Questions:● What is the statistical commonality of secondhand stroller purchase?

○ How many times will a stroller get resold, on average?● What are specific behaviors of parents that commonly lead to injury of children, or that

are riskier in general?○ Are there injuries that could be avoided by making parts of the strollers less

complex or time consuming to work with?● What is the commonality of children unbuckling their harnesses because they were

uncomfortable?○ If common, how can harnesses be made more comfortable?

● How do the mechanical functions of various components of the stroller specifically operate, like clips or latching mechanisms?

● What are the specific characteristics of each of the materials that strollers are made out of, and what characteristics would be most important to safe stroller design?

● How many injuries are the result of faulty wheel locking?● Parent preference of strollers vs harnesses

Action Items:

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● Additional Interviews/Observations: Now that we have a clearer vision of what Mrs. Cowles wants from us, and the additional information she provided, we should be able to begin interviewing various other individuals about the problems of stroller use and safety. We will be receiving a list of places which have both experts on infants and strollers we can interview, as well as many users (parents) who we can interview and observe to obtain other insights into the problem. User interviews are especially important to schedule, since our users are parents with infants, and are going to require some. We also should follow up with Mrs. Cowles for the purpose of answering more question that arise.

● Further Research: As stated under the perspectives section, there are several area of research that can be pursued independently by members of this design group in order to answer questions remaining from the interview, and new questions that have arisen from the interview.

● Brainstorm: With the information from this interview and our secondary research, we can now begin to generate ideas for potential improvements to stroller design.

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Appendix D: User Observation Summary 1

Date: 10/09/2016Time: 12:00 to 1:00 PMLocation: Northwestern University Lake fillKey People In Attendance: Jacob HechterConditions of Environment: Sunny, Chilly, which a breeze

IntroductionOn 10/09/2016, Jacob Hechter went to the Northwestern University Lakefill to observe parents pushing using strollers. The purpose of this session was to gain some basic insight into the behaviors of parents as they use strollers. The observation lasted and hour total, but only three strollers were observed during that time. This summary explains the methodology and results of this observation. The weather was sunny, chilly, and with a breeze.

MethodologyThis took place on the various paths around the Lakefill. Users were observed as they walked around the Lakefill with the strollers in use, and specific points of interest and deviations from expected stroller uses were noted.

Information About UsersThere were three user groups observed. Group 1 was a father, mother, and child group. They were using a standard, 4 wheeled stroller. The strollers manipulating mechanism had two vertical bars on the ends, which the father grasped while pushing. The stroller was being pushed by the father. Group 2 was a large group, most likely two families with 4 young children total. They possessed a stroller, but no child was in the stroller. The stroller itself was being pushed by one of the older children. Group 3 was a father, mother, and child group. They were using a standard, 4 wheeled stroller. The stroller was being pushed by the father.

User Interactions and Deviations from Expected BehaviorThe father in group 1 was pushing the stroller forward, generally leaning forward slightly as he pushed. The point of interest here is how he turned the stroller. The run in question was a very gentle right turn, along a gently right curving path. See Figure 6 for visualization.

1. Released both hands from the stroller push bars2. Moved both hands to the right side of the stroller3. Griped the right vertical bar with both hands4. Seemed to pull the right side towards himself, as method of turning the stroller5. Released with both hands6. Moved hands back to original position

Group 2’s stroller was, as indicated above, being pushed by one of the kids. The kid had the stroller tilted, so it rested on its back wheels, and was moving it around like described. The father in group 3 did not display any deviation in usage with the stroller. The only piece of information to add was that he was carrying a camera over his shoulder, which might possibly interfere with stroller use.

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User Observation Table:

Table 2: Major User Observations 1

Observations Opportunities Follow-ups

One user let go of the stroller for a moment to reposition his hands in an attempt to gain better leverage to make a gentle turn.

Alter the design of the stroller to make it more maneuverable.

Look into other 4-wheeled products for ideas into maneuverability.

Strollers are sometimes wheeled while they are actually not in use, with the theoretical occupant walking

Compact down into an easy to carry, wear, or store format.

Ways of reducing weight and making easier to store.

Figure 6: Drawing of Shifting Hand Positions

A visualization of the process by which the fathershifted his grip on the stroller handle.

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Appendix E: User Observation Summary (10/10/16)

IntroductionJaelon Woodard observed a user of a stroller at her apartment complex’s greeting room on October 10, 2016 at 2025 Sherman Avenue Evanston, Illinois. Jaelon Also spoke with the user, professor Cole, as well as her daughter, Evelyn, in order to learn how they felt about the strollers they have and their experiences. The purpose of the observation was to learn exactly what they use the stroller for, why they got the specific kind, what they like about them, and their grievances with the ones they have. The observation lasted for fifty minutes, from 5:10 PM to 6:00 PM.

MethodologyThe observation took place in the greeting room of an apartment complex. The user and her daughter had two strollers with them, which were different in design and practical use. The user was asked how she felt about her strollers, what she would change, and how she would make a stroller better fit her needs. The user was then asked to condense and expand both strollers. Finally, Evelyn was asked what she liked about the strollers.

Information about the users and their strollersProfessor Cole is a former DTC teacher and her daughter, Evelyn, is about two and a half years old. They obtained one stroller for free from a friend and another one for free from a baby store. They use the hand me down, which is much larger and heavier, for long distance walks and when they need the extra storage. They use the other stroller, which is much lighter and doesn’t have storage space, for shorter walks.

These were the main characteristics that she wanted in a stroller:● Lightweight● Intuitive to fold/unfold● Storage space● Easy to get over cracks in sidewalk● Better maneuverability to turn tight corners● A tray for the child to put snacks● Easily removable seat cover for washing

User’s interactions and difficulties with their strollersHeavy Stroller:

● One difficulty is that there’s no way to know whether the stroller is locked/unlocked to fold and unfold. Also, the process is difficult and requires two hands and a foot, meaning the child can wander away.

● Another difficulty is that the seat cover gets dirty and isn’t easily removable for washing.● Another difficulty is that the stroller is heavy, so it’s harder to push and maneuver in tight

spaces.● One benefit is the roof that goes all the way down to shield the child from bad weather.● Another benefit is the storage space.● Another benefit is the tray for the child’s snacks.

Light Stroller:● One difficulty is that the stroller has no roof.

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● Another difficulty is that the stroller is very flimsy, so going over cracks in the road can sometimes almost cause the child to fall out.

● Another difficulty is that there’s no storage space.● Another difficulty is that there’s no tray, so if the child wants to eat there’s a great chance

they’ll get dirty.● One benefit is that because it’s lightweight, it’s easier to push around.● Another benefit is that it’s much easier to fold and has a visible cue to know whether it’s

locked or unlocked to fold up or unfold.

User Observation Table

Table 3: Major User Observations 2

Observations Opportunities Follow-up

User had difficulty folding and unfolding.

A more user friendly and less intensive folding mechanism with feedback.

Make a more intuitive to use locking system

User has two strollers to cover all the functions necessary

Take best aspects of both to make one stroller, less money than 2

Make storage space on a lightweight stroller

User has trouble turning the strollers in tight spaces

Make wheels with a better turning radius

Replace wheels or revamp the structure of leg/wheel connection

Excessive features that aren’t intuitive to use

Strip down the superfluous functions that aren’t key to safety and basic comfort. This helps the weight

K.I.S.S. approach to making the stroller. Make it safe but simple.

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Appendix F: Mockup Documentation

Introduction:The stroller mockup (Figures 7, 8, 9) was constructed from the frame of a (Insert brand here) umbrella stroller. The stroller had its seating removed, to make space for working with and altering the stroller. Various points on the stroller were cut, for the purposes of making the stroller base adjustable beyond what was allowed by the stroller initially, to test different base configurations for stability. The back wheels were sawed off and replaced by two large wheels on an axle (Figures 11 and 12), to test if the stroller stability was improved by increasing the size of the back wheels. The front wheels were taped in place to construct a front axle (Figure 13) which can be steered by pulling upon the reigns (Figure 14) to approximate some method of front wheel steering, be it a bar like in the mockup or a steering wheel. The stroller also possesses a dashboard with lights which alert the user to one of five potential dangerous situations (Figure 9). These dangerous situations are: the stroller tipping, the stroller’s restraints being undone, the being structurally unsound because it was not unfolded all the way, the wheel lock not being engaged, and the stroller having unbalanced weight which may cause tipping.

Figure 7: Front View of Mockup Frame Figure 8: Side View of Mockup Frame

Figure 9: Top view of the Mockup Figure 10: View of proposed dash board handle

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Figure 11: View of Steering Reigns Figure 12: View of Back Axle and Wheels

Figure 13: View of Back Wheel Figure 14: Front axle and wheels

The Seat Mockup was constructed for the purposes of testing improved stroller comfort for the child. It consists of a hard foam core shell (Figure 15), with strips of hard foam on the inside of the seat, covered by felt (Figure 16). The mockup was specifically created to test if the child was more comfortable with a seat with a great deal of rigidity and structure, which would support their body better than a softer material.

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Figure 15: Front and Inside View of Seat Figure 16: Side and outside view of Seat

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Appendix G: User Testing Summary 1

Date: 10/28/16Time: 7:15 pm - 8:15 pmLocation: The user/expert’s office, Ford BuildingKey People in Attendance: Annick Nshuti (Author); and the Users/expert Prof J Alex BirdwellConditions of environments: In the user's office, specifically outside the office itself(lobby), (the stroller was not going to fit in the space in the office)Condition of users: Comfortable, Unstressed, Timed because he had other people to talk to after

Purpose:

The purpose of the user testing was to get user feedback on our design concepts, and to therefore determine if our design ideas were feasible and appropriate from a consumer perspective. The specific concepts that were shown to the user/expert for the purpose of the testing were: (1) The integrating of a larger wheel base as a way to improve the weight distribution over the stroller and increasing its overall stability,(2) The use of electronic visual and sound feedback to warn the user of dangerous situations, and(3) The integrating of 360-degree freedom front wheel and larger wheels in the back for improved stroller maneuverability.(4) The use of hard foam and sturdy backing for the seating

Testing Methodology:

This design review was performed by Annick Nshuti, who had brought the mock-up to perform user testing with Prof J. Alex Birdwell at his office on the 2nd floor of Ford building. Because of the incompleteness of our mock-up, the explanations went further to drawings, verbal descriptions, and storyboards. After thoroughly explaining the features that our final design would integrate we set forth questions we had for our user/expert. Notes were taken based on user feedback.

Questions:

1. To what extent do you think our design addresses the safety issues that are common in current strollers?

2. Is the idea of integrating of the auditory and visual feedback worth the effort? 3. After hearing and observing our design ideas, what do you think can be improved on it?4. Is there something missing that you expected?5. If you could change a thing on our design what would it be? 6. Any comments or questions or further thoughts on our design?

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Results/User Feedback:

Table 4: User Testing Results 1The problem we are solving

Description The user’s feedback Other Suggestions

Stability problems Integrating a larger wheelbase, and bigger back wheels

The back wheel can easily cause the tipping over if they are large and heavy.

Bring the back-wheels backwards, in a way that doesn’t make the person’s feet hit the stroller.

Decrease the seat elevation

Maneuverability of a stroller

1.360-degree freedom for the front wheels2. A steering bar to turn the stroller

The user thinks these two will solve the maneuverability problems in a daily use of a stroller despite the fact that our mock-up didn’t have them integrated yet.

Electronic system The auditory feedbackThe light feedback

The auditory feedback would be much more efficient and the best way to alarm urgent hazards like a tip-over

This will require mechanical skills that we are not equipped with yet.The user suggests we start using the mechatronics lab.

Referred us to Prof. Nick Manchuk, FordB.100

Comfortable seat Foam straps under the seat

Seat of any made stroller is generally comfortable.

The user suggests we focus on solving the above problems and may be get a seat from another stroller or just buy a more comfortable car seat.

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Questions that emerged from our user-testing with Prof Birdwell:

Will our design integrate any storages?

Does opening the hinges interfere with the entire safety of the stroller?

What will power our the electronic system?

Can sensors replace the light warning system?

Conclusion:

The suggestions and feedback from the user/expert testing will help our group as we work toward making our final mock-up specifically making use of sound for a tipping warning and making use of vibration for a disengaged or failed seat belt as well as integrating a larger wheel base and bigger back wheel that run towards the sides of the stroller.

Limitations:

One of the major limitations was that due to the time-frame our mock-up was unfinished and this made some features hard to understand for our user during the user testing. Secondly, this prevented the users from interacting with the mockup, and providing feedback because of their interactions, and as a result their feedback may not reflect the actual user-interaction with the stroller. Time was also relatively not really enough and definitely more topics could have been discussed about.

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Appendix H: User Testing Summary 2

Date: 11/01/16Time: 7:15 pm - 8:15 pmLocation: The user's home, Key People in Attendance: Jacob Hechter (Author); Representatives of the other three teams; and the Users, Jamie and Lauren ZuercherConditions of environments: In the user's home, specifically the living roomCondition of users: Comfortable and Unstressed

Purpose:

The purpose of the user testing was to get user feedback on our design concepts, and to see if they were viable and desirable from a consumer perspective. The specific concepts that were shown to the users for the purpose of the testing was: (1) The use of hard foam and sturdy backing for the seating (2) The use of electronic feedback to warn the user of dangerous situations and (3) The use of a front wheel steering system.

Testing Methodology:

This design review was performed by Jacob Hechter along with representatives of several other teams who also traveled to perform user testing with the Zuechers. Because of the difficulty of transporting the mockup due to its size, testing was done through the use of drawings, verbal descriptions, and storyboards. Notes were taken based on user feedback. Notes were also taken on the feedback given to other teams

Results/User Feedback:

Other User Testing● Multiple Pocket action is nice, but bigger pocket action is best● Side by side double stroller● Magnet to keep the straps out of the way – huge thing!!!● Son will always favor one side of the stroller, and lean on that size when sleeping● 2-3 year olds are crazy, trying to get everywhere● Hard metal thing around a child’s neck would cause them to go “ape”● Charging for parents

○ Parents are going to forget a ton of stuff, including charging● They love the roller coaster design, because of simplicity

○ “Throw them in and shut it down”● For a thing that stops the stroller when you let go of it, making it stop immediately would

be disastrous

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○ Cause people to fall and trip and all kinds of awful things● Multiple places to charge the battery● Parents purchases are about pragmatism and multiuse – want the stroller to be simple● Parents Want children to sleep as much as possible if focusing at 0-6 months● For the first year, parents are terrified the baby is going to die● A good consumer goal would be to Maximize sleep-ability for maximum

Our User Testing● Light would be tough

○ Tough to see in bright light○ Audio can startle the baby and wake them

● Child will sink into the stroller● Always leaning one side● Sensor to check to make sure they aren’t leaning on the straps● Vibration sensor

○ So you get feedback but the babies don’t● Suburban parent vs city parent● Preventing a stroller from being stolen – Bluetooth connection● Age dependent comfort

○ Don’t want things that can jostle and transfer lots of energy○ Kids aren’t active until like 6 months○ More important to ensure something to entertain them – more fidgety when not in

motion● Push car – 1 handle● Babies take up 80% of your brain – needs to be idiot proof● Plan for a baby that’s fighting the parent

Analysis:

Electronic Feedback: The use of a light to warn parents of a danger in the stroller is likely to be ineffective, as a result of any light being generated being difficult to see in bright conditions. The use of a sound for warning of non-immediate is also problematic, because of the potential to wake up the child, an outcome that users desire very little. The use of feedback that is easy for the parents to detect but hard for the child to detect is the goal, and vibration is one such method. The users also recommend a Bluetooth application to let parents know that the stroller is moving if they are not using it, to warn of danger and to warn of people trying to steal the stroller.

The Seat: The use of a solid structure and hard foam appears to be a possibly damaging idea, as the increase in energy being transferred into the child in the stroller due to increased rigidity may be a serious health concern. They mentioned that they would prefer some method of entertaining the child to be added to the stroller, such as a toy steering wheel. This is in line with research

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that suggests that children are most likely to fall out of strollers when the stroller is stopped and they are no longer distracted by the motion and changing scenery.

Front Wheel Steering: Mentioned the idea that, instead of a steering bar or wheel, the design should incorporate a handle similar to a push car.

Other: The design needs to be prepared for a non-compliant infant, and needs to be designed so that an exhausted parent with 80% of their thought process taken up by their child can make use of the stroller. Making strollers easier to use and designing it to remove common inconveniences would significantly increase user value and appeal.

Conclusion:

The refinements described in the analysis will be made to the design, specifically making use of sound for a tipping warning and making use of vibration for a disengaged or failed seat belt. These general improvements to reduce user effort when making use of the stroller is also a good direction to take design.

Limitations:

One of the major limitations was the inability to actually transport the mockup for the purposes of user testing. This prevented the users from interacting with the mockup, and providing feedback because of their interactions, and as a result their feedback may not reflect the actual interaction with the stroller.

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Appendix I: Design Review Summary

Date: 11/09/16Time: 4:00 - 4:40Location: Ford DTC ClassroomKey People in Attendance: Jacob Hechter, Annick Nshuti, Jaelon Woodard, Bharat Rao, remainder of DTC Section 16, Professor Carmichael, Professor Bedell

Table 5: Design Review Feedback

Categories Positive Comments

Negative Comments

Features to Add

Features to Remove

Other Comments

Wheel Base/Structure

Possibly increase folding compatibility

Need to consider air filled wheels vs solid rubber wheels.

Front wheel Steering

The method may generally reduce maneuverability

Can put large amount of weight on the front wheels, which when fully turned, may

May just remove this feature altogether

We’re doing a lot with this mock-up, and we may wish to back off and focus on fewer things, and cut out something high effort/low reward like this

Could possibly encourage one-handed steering

Toy Steering Wheel/Entertainment

Current method of creation is very complex, and could

Folding mechanism, just make it so it can be detached and reattached

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possibly cause harm to child

easily

Warning Sensors

Existence of sensors can warn parents and others to dangers which may have otherwise gone unnoticed, and save lives.

Without some method of turning it off, could become an annoyance to the parents

Nearby wires may be dangerous to child

Some method of disabling the sensors when the stroller is not in use, so as to not annoy or frustrate the user (Pressure sensor or off switch)

Make use of a 2-axis gyroscope instead of a 3-axis, since we only care about two axes.

Needs to account for things like sudden stops and the parent popping a wheelie

Table 6: Changes Based On Design Review

Concern Change

Need to prevent false alarms for sensors to reduce irritation and frustration due to those false alarms

Pressure Sensor, which senses when the stroller is occupied. Or add an off switch, to allow the parents to turn the warnings on and off.

Pressure sensor to detect the variation in pressure on the wheels. (tipping)

Need to ensure the safety of the child due to possible electrical danger

Insulate wiring well and keep as far out of the child's reach as possible

Front wheel steering may reduce maneuverability

Will likely remove from final design, to free up time, money, and other resources.

Steering wheel may pose a hazard to the child Reduce complexity, and make it very easy for parents to remove.

Keep all possible pinch points far out of child’s reach.

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Appendix J: Project Freeze Documentation

Date: 11/10/16Time: 9:00 - 11:00 PMLocation: Ford Breakout RoomKey People in Attendance: Jacob Hechter, Annick Nshuti, Jaelon Woodard, Bharat Rao

Design Freeze Documentation: Safer Stroller

Design Description:

Our team envisions our design as being more stable and maneuverable than the common stroller. Our design also addresses the need for the child to be distracted, in order to minimize the self-inflicted risk of falling out of the stroller.

Our design will look like a typical middle-high end stroller but with several modifications to its structure. The wheelbase will be wider so as to provide a more even spread of the weight from the child. The structure of the stroller itself will be made from aluminum piping, as it’s lightweight and easy to manipulate but strong and supportive.

We will also use wheels that are larger in the rear with smaller wheels in the front in order to offset the possible extra weight from the child either leaning back far in their seat, or from the parent resting extra weight on the steering handle.

Another feature our design will have is electronic sensors to emit a sound when the stroller is about to tip, or vibration if the seatbelt is unlocked. This will provide extra safety as the parent will know whether their child has managed to unbuckle themselves or provide an increase in reaction time to potentially stop the stroller from tipping over.

Additionally, we will place a removable toy steering wheel in front of the child’s seat. The aim is to provide something that can distract the child and keep them occupied. When a child isn’t occupied, that’s usually when they can get themselves into safety issues or get distracted by something they can’t reach, so they try to get out of their stroller which leads to them tipping it or falling out.

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Table 7: Bill of Materials

Item Description Quantity Vendor Part Number

Unit Cost Total Cost

Arduino Board module that will power the sensors in the stroller

1 Arduino N/A $30.00 $30.00

ALEKO® BS-MC12S 1 Set Magnetic Contact Reed Switch

Magnet and reed sensor that will transmit and sense when seat belt is clicked and fastened

1 Amazon BS-MC12S $4.79 $4.79

Aluminum piping Unpolished General Purpose Aluminum Tubing:• 0.065‘” wall thickness•1" outer diameter•3' length

1 McMaster-Carr

89965K681 $19.41 $19.41

Toy Steering Wheel Baby And Toddler Car Driver With Driving Tunes - Take Along Toy

1 Amazon N/A $9.99 $9.99

Vibrating Motors DIY Mini Vibrating Motors

1 Amazon N/A $7.99 $7.99

uxcell 20 x Micro Limit Switch Long Hinge Roller Arm

Set micro limit switches which will be used to determine if a child is in a seat.

1 Amazon s14031900am1446

$8.32 $8.32

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Figure 17: Orthographic View of Overall Structure

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Figure 18: Isometric Drawing of the overall structure

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Figure 19: Vibrating Stroller Handle

Figure 20: Seat Belt Sensor

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Figure 21: Toy Steering Wheel

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Appendix K: Prototype Construction

The following is a table of the materials needed for altering an already made stroller.

Table 8: Materials for Prototype Construction

Material Quantity

Arduino 1

Toy Steering Wheel 1

Vibrating Motors 1

uxcell 20 x Micro Limit Switch Long Hinge Roller Arm 1

ALEKO® BS-MC12S 1 Set Magnetic Contact Reed Switch 1

Note: The bill of materials has more specific information for each part used and the cost of individual parts.

Tools used for construction:

Lathe Vertical band saw Phillips screwdriver Power drill Taps Screws Hand saw Hot glue Meter stick Wire cutters Drill press

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Extending the Wheel Base1. Cut off the back wheels of the stroller using a vertical band saw

Figure 22: Back Wheel2. Sand the cut aluminum frame. 3. Drill through the aluminum rods in order to place a screw of your desired size4. Acquire another aluminum rod and drill through it at the same size5. Screw the rods together orthogonal from each other

6. Drill through the other end of the new wheel base at a predetermined size7. With your chosen set of wheels(preferably larger),  attach them to the wheelbase with

screws and use a nut to secure them in place.

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Figure 23: Aluminum Rod Attachment

Implementing the Toy Steering Wheel 1. Take an aluminum scrap metal rod2. Place it in the drill press and drill a hole in the exact center of the rod 3. Make the hole the same size as the screw you wish to use4. Tap the rod so it has ridges for the screw5. Remove the steel rod and place it in a lathe6. Drill a hole on each end of the rod at your predetermined size7. Tap the ends so screws can be inserted8. Drill two holes on the sides of the stroller where you will place the bar9. Screw the bar into place10. Take another steel rod and thread the end of it so it can be screwed into the other rod11. Hot glue the steering wheel onto the end of the inserted aluminum rod so it’s in front of

and facing the infant

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Figure 24: Fully Assembled Frame Extension

Implementation of Electronics Set up a circuit that contains two limit switches One switch needs to detect whether or not the seatbelt is engaged The other switch needs to detect the child sitting in the seat Both switches must be engaged, or else the vibrating motors will be engaged within the

steering handle

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Figure 25: Assembled Toy Steering Wheel

Figure 26: Electronics

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Appendix L: Individual Research | Bharat Rao

Introduction The nature of the stroller market may help determine how our design can become more competitive, nonconformist, and powerful. By understanding how the macroscale market and microscale stroller industry function, the design team can make inferences about the specific parts of the stroller that firms manufacture to gain a competitive edge in the market. The process to gain this edge can enlighten us as to what we need to do to be competitive in this market while building a safer stroller.

MethodsThe gathering of sources began in the first week of October and ended in the second week of November. Literature and sources were reviewed based on their relevance to various topics. These topics include specific competitors in the stroller market, market share of strollers that cater to a specific need, parts of the stroller, stroller benchmarks, the best stroller brands, and the growth of the stroller market. Consumer and ranking reports provided insight into the stroller benchmarks and top stroller brands in the market. Strollers, like many other products, are subjective, meaning using the word “best” to describe a stroller is not particularly correct. Different users with different needs will prefer a different stroller than some other user. However, comparing the consumer and ranking reports with one another and highlighting similarities between the strollers that are consistently ranked in the top provides evidence of specific features and benchmarks that consumers prefer. Additionally, stroller brands that are consistently at the top of the consumer and ranking reports are the brands that create these benchmarks, or barriers to entry. The competitive nature of the market is dependent upon how other companies can mimic or exceed the benchmarks that the top stroller brands are setting. Company websites such as Britax’s, Bugaboo’s, and Thule’s, proved to be the most helpful in revealing the key features of the brands’ specific models. The websites were accessed early in the research process to highlight the key features that made-up standards and benchmarks. Highlighting only the brand and not their specific models was unhelpful in drawing a conclusion about the dominance of one or two specific firm(s). The features fall under the following three categories:

● Maneuverability ● Ease of use● Safety

The above features and their relevance to designing a stroller that meets certain benchmarks can be addressed by analyzing the websites and brands’ strollers through pictures and feature descriptions. Again, multiple stroller brands have different strollers that they design to cater to multiple types and groups of consumers; however, determining the features that are common to all models helps establish the benchmark for strollers among firms in the market. Market share of specific firms, growth of the stroller market, and specific competitors in the market are topics that were covered in business databases such as IBISWorld and in finance related publications such as Bloomberg and Businesswire. Finance publications and business databases were accessed for a short period, one to two days, due to the type of information they offered. Most of the information could be easily parsed because it was all quantitative. Simply putting these numbers in the context of the stroller market was all that was necessary to understand what they meant. Unfortunately, there was no accessible data online or in text that told of a specific firm’s

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market share. The stroller market is quite specific, and a lot of stroller companies are subsidiary companies of bigger vendors that participate in producing and selling a variety of items. Although this data was not available, the data that was offered a different perspective from the company websites. Where the company websites provided a more design oriented perspective qualitatively, the databases and financial literature provided a more business oriented quantitative approach to solving the problem. The following information details the results of the research in three categories: competitors, benchmarks, and changing standards via design choices.

ResultsThe following data and results help in narrowing the goal of building a safer stroller. To build a safer stroller that consumers are willing to buy, the product must first meet the standards and benchmarks that other firms have established. Products that do not meet standards set by other firms rarely survive for long in the hypercompetitive nature of markets. In other words, for the product to reach the user, it must be competitive. The competitiveness of the stroller is dependent on the features that it provides, and whether these features compare to the features of strollers already on the market now. Getting familiar with the benchmarks, standards, and firms is a step in designing a competitive, safe, and powerful stroller. For the sake of simplicity, the three categories above (maneuverability, ease of use, safety) will be the measures of stroller quality. These three categories were not randomly chosen but were the common ways of ranking strollers among consumerreports.org, babygearlab.com, and ranker.com, and therefore they will be the ways of defining stroller quality in this appendix. Determining the benchmarks and how firms are redefining them as well as identifying the firms and the emergence of new competition will help Team 16-4 design a safer more competitive stroller.

CompetitorsThere are tons of vendors in the stroller market. The lack of data regarding specific firm’s market share demonstrates that not one specific company dominates the market. However, there are other measures that reveal important pieces of information in designing a competitive stroller. Geographically, there is a dense market share in Europe compared to that of any other country. According to Technavio, a market research firm, the geographical segment of global baby stroller market share in 2015 via percent of revenue was in Europe, at 42.33% (Technavio, 2015). PR Newswire writes that the reason for the dense market share in Europe compared to other countries like the United States is because of “the improvements in product quality along with rising demand for multifunctional and convenient baby travel gear and decreasing price amongst the population” (PR Newswire, 2015). This data also highlights an important misconception among consumers in the United States that strollers are mostly American made, when in fact, two key vendors in the stroller market, Bugaboo and Thule, are currently headquartered in Europe (Bugaboo International, 2016; Thule, 2016). Despite of the differences in market share segmentation geographically, overall growth in the stroller market is expected to rise. IBISWorld predicts that there will be 3.1% annualized growth until 2020 for the stroller industry highlighting that strollers are becoming a lifestyle for not only families in Europe but all around the world, as well (IBISWorld, 2016). The specific models and features that are associated with the strollers families are buying are representative of the type of lifestyle that the families are living. In 2015, 37% of the market share was comfort strollers highlighting a need that consumers have for multipurpose products (PR Newswire, 2015). Comfort strollers are ones

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that can be used for a variety of purposes. This will be highlighted in the next section. Essentially, what this quantitative data reveals, especially the geographical segmentation of market share, is that not only are stroller sales expected to increase, but that specific models and features of brands are catered to specific lifestyles. The lifestyle that families live in Europe may call for a drastically different stroller than the lifestyle that families live in the United States. Since our product is being considered among American consumers, this data tells us that we must consider the American lifestyle. Again, Technavio states that “baby strollers and prams such as joggers are especially very popular in the US” revealing that the nature of lifestyle in the United States may be one where users enjoy participating in some activity, hence a jogging stroller is more fitting, whereas compared to Europe, the lifestyle is more relaxed and calls for a comfort stroller instead (Technavio, 2015).

Benchmarks Companies and their manufacturers design strollers that meet a consumer’s specifics needs. In this way, some stroller companies have a niche market; however, this niche market is the result of a specific model of stroller that the brand has built. Stroller brands themselves diversify as much as they can to target as many different consumers as possible. The goal of this section is to analyze and highlight the features that are common among various models and brands of strollers to create a benchmark for production. Among the strollers ranked on consumerreports.org, the

Britax B-Agile 4 stroller is one of the highest ranked strollers with a score of 83 out of 100 because it is “Compact and sturdy, with excellent maneuverability. Car seat compatible as sold. Generous canopy with mesh for ventilation, and a large storage pocket, too. Very easy to fold/unfold.” (ConsumerReports, 2016). On babylist.com, a model like the B-Agile 4 by Britax makes the “Best Strollers of 2016” list for its ease of use. One parent saying “I love this stroller because it is basically idiot-proof. It has one-button press and a handle you lift on to collapse. It comes with a collapsible sunshade, newborn headrest and converter clips that allow you to pop the infant car seat into the stroller for easy transition from the car. I couldn’t be more satisfied!” (Babylist, 2016). On ranker.com, Britax ranks number one for best stroller brand of 2016 and has 47 up-votes (Ranker, 2016). The similarities between these two models of stroller are quite clear. It is extremely easy to use, which is clearly a facet of strollers that parents care about a lot. Britax, being consistently ranked in the top five among different ranking sites, proves that it is producing strollers that do not require much assembly or time to get used to. Established benchmarks among the ease of use category could

be compactness, large storage, and easy folding. Additionally, on the safety front there are similarities among strollers on different reports and rankings sites. For example, the Chicco Activ3 Stroller, rated 81 out of 100 by ConsumerReports “performs well on all types of terrain… and contains the hand-operated brake” (ConsumerReports, 2016). The Bugaboo Buffalo Stroller and BOB Motion Stroller, ranked fifth and sixth respectively, for “Top 10 Standard-sized Strollers” on diapers.com exhibit the ability to ride on all terrains because of their multifaceted suspension system. (Diapers, 2016). Safety and maneuverability standards can be discussed with

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these reviews. A strong suspension system is a benchmark for safety due to the ability to minimize impact of large bumps on terrain and in turn minimizing the irritation the baby feels while sitting. A summary of some of the benchmarks and standards along with models can be seen in the following table:

Table 9: Safety, Ease of Use, Maneuverability Benchmarks of Top Ranked Strollers

Model Safety/Maneuverability Benchmark

Ease of Use Benchmarks

Britax B-Agile 4 Compact and sturdy Canopy with meshEasy fold/unfold

Chicco Activ3 Hand-operated brakePerforms on all terrain

Easy fold/unfoldAdjustable handle

Britax B-Agile 3 Compact and sturdyWide wheel base

Handle to lift up to fold/collapseConverter clips

Bugaboo Buffalo Very roomy seatAll terrainVersatile suspension

Small hooksBasketCanopyEasy fold/unfold

BOB Motion Rugged suspension system LightweightCompact

Looking at the bolded features, it is evidently clear that the benchmarks for a competitive stroller in the market are easy folding, compactness, sturdiness, and high performance on all terrains (ruggedness). An interesting point to note is that in the research process, reviews and reports regarding stroller features were mostly written about ease of use and not about safety implying that parents or guardians, when purchasing a stroller, assume that the product they are investing in is safe. Regardless of the assumption that consumers make however, the above standards are just some of the features that make a stroller competitive in its respective market, and building a stroller around these features, or at least some of them, will help it penetrate the market better.

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Key:Bold: Features common among strollers listed

Source: Babylist, ConsumerReports, Ranker(https://www.babylist.com/hello-baby/best-strollers)(http://www.consumerreports.org/cro/strollers.htm?loginMethod=auto)(http://www.ranker.com/list/stroller-brands/werner-brandes)

Figure 28: Basic lightweight umbrella stroller

Source: Toys R’ Us (http://www.toysrus.com/product/index.jsp?

productId=70034306&gclid=CJONwaCqsdACFQyUaQodWlIKmw&camp=PLAPPCG-_-PID22065439:BRUS&cagpspn=plab_22065439&eESource=CAPLA_DF:70034306:TRUS

)

Figure 29: Bugaboo Cameleon 3 Stroller

Source: Bugaboo International (https://www.bugaboo.com/US/en_US/str

ollers/create?sId=CAM3STD&gclid=CIXLloyrsdACF

ZKCaQod66YDHA)

Changing Standards via Design ChoicesThe most successful firms are ones that make their brand visible to consumers. Evidenced by the table above, features that consumers have considered when buying a stroller center around how easy the product is to use and its safety and maneuverability. The features that high grossing stroller companies have chosen to integrate are the features that make up the product benchmarks on the stroller market. Though, certain brands, like Bugaboo, are introducing completely new benchmarks that were previously not considered by companies.

AestheticsAesthetics has become an integral part of how strollers get sold. Different brands have undertaken challenges to divert from typical design choices. One example of this diversion is the urban assault stroller. Urban assault strollers are more common among younger parents and guardians today. They are wider and offer bigger bases that do not fit on normal sized street sidewalks. Urban assault strollers are just one exhibit of nonconformist designs in stroller companies. Diverging from the typical stroller building path, with a simple metal chassis with canvas seating, Bugaboo strollers break the common stereotype of how a stroller should look (Hogue, 2005). Bugaboo’s urban assault strollers are versatile and rugged per Stuart Hogue of the Design Management Review. Additionally, Hogue states that “self-expressive products like the Bugaboo succeed by producing cognitive dissonance in

observers. Observers experience cognitive dissonance as they wrestle with the tension between their expectations for a product and its actual design. It used to be that a stroller needed only to be lightweight and compact to be successful. People did not expect Euro-styling and ruggedness in a category traditionally defined by basic utility. By countering these expectations, the Bugaboo relies on cognitive dissonance to increase the amount of time observers spend considering the product and its users (Hogue, 2005).” The first invention of the stroller has evolved into what has been identified as the standard stroller today. Now, identified as the standard stroller because of its evolution from the original stroller, the canvas seating and metal chassis design are considered conformist due to their lack of originality.

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AnalysisQuantitative data targeting market share, specific competitors, and market growth reveal that the stroller market is on the rise. Additionally, the data highlights changing preferences among different groups of consumers geographically. The varying interests among consumers also motivates companies to diverge from their typical manufacturing processes to produce strollers. Instead, companies are on the verge of designing atypical products to create and establish new benchmarks to attract users. Bugaboo’s wide base design of their urban assault stroller is indicative of how changing the overall design of the chassis can have an impact on the consumer’s choice. The design choices that Bugaboo made for their urban-assault stroller is an example of using nonconformist design to appeal to consumers. We can draw influence from Bugaboo by building parts, and a stroller that stands out from typical strollers in the industry right now to gain a competitive edge. Lastly, it is important to target a specific consumer with our design problem. Safety is the number one priority of our design; however, it is imperative to build or modify a stroller that targets a niche group of consumers with a certain lifestyle all while maintaining the benchmarks that current strollers on the market have set, or creating or own. DiscussionIt is blatantly clear that the stroller market is not as simple as initially anticipated. As noted above, some companies are attempting to break typical designs and processes to stand out in a market that is divided among numerous stroller producing firms. Designing a safer stroller is not the only dry way to address the design problem at hand. After conducting research, it must be noted that there are many factors to consider when designing our stroller with a priority on safety:

● How does the stroller appeal to the kid and guardian? ● Can the stroller’s design be considered atypical? ● How can we build a stroller that increases the barrier to entry in the hyper competitive

stroller market? ● Can our stroller meet or exceed the standards/benchmarks that are set by current strollers

on the market?o If so, how?

These are all questions that need to be considered when working and designing in the future, and answering these types of questions will prove beneficial in ultimately solving the design problem at hand: building a safer stroller.

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Works Cited

BabyGearLab. (2016). Best Baby Strollers of 2016 | BabyGearLab. Retrieved November 18,

2016, from http://www.babygearlab.com/Best-Stroller

Babylist. (2016). Best Strollers. Retrieved November 18, 2016, from

https://www.babylist.com/hello-baby/best- strollers

Brandes, W. (2016). The Best Stroller Brands. Retrieved November 18, 2016, from

http://www.ranker.com/list/stroller-brands/werner- brandes

Bugaboo International. (2016). The story of us. Retrieved October 24, 2016, from

https://www.bugaboo.com/US/en_US/about

ConsumerReports. (2016). Top Stroller Reviews | Best Stroller – Consumer Reports. Retrieved

November 18, 2016, from http://www.consumerreports.org/cro/strollers.htm

Hogue, S. (2005). Making Designs Dissonant. Design Management Review, 16(4), 34–38,86.

IBISWorld. (2015). Durable Baby Goods Stores (IBISWorld iExpert Industry Summary No.

OD4386). Melbourne, Australia: IBISWorld Services. Retrieved from

http://clients1.ibisworld.com.turing.library.northwestern.edu/reports/us/iexpert/default.as

px?entid=4386

Newswire, P. R. (2015, December 30). Global Baby Stroller And Pram Market 2016-2020.

Retrieved November 18, 2016, from https://www.thestreet.com/story/13409619/1/global-

baby-stroller- and-pram- market-2016- 2020.html

Technavio. (2016, February 18). Improved Functionality and Performance Will Drive Global

Baby Stroller and Pram Market Until 2020, Says Technavio | Business Wire. Retrieved

November 18, 2016, from

http://www.businesswire.com/news/home/20160218005039/en/Improved-Functionality-

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Performance-Drive- Global-Baby- Stroller

Thule. (2016). About the Thule brand | Thule | USA. Retrieved October 24, 2016, from

https://www.thule.com/en-us/us/about- thule/about-the- thule-brand

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Appendix M: Individual Research | Jaelon Woodard

The inquiry explains what the long term effects of brain trauma are and how they affect the individual later in their lifetime. By knowing the gravity of the safety issues that can arise when manufacturing a stroller, companies then know how to better manufacture strollers in order to avoid brain damage accidents to infants.

Search Methods

The search method implemented for this inquiry was to examine scientific databases focusing on biological experiments and databases dealing with engineering and manufacturing. The databases used include ebscohost and scopus. Key words used to help find preliminary articles include: stroller, head, trauma, concussion, brain, infant, development, disabilities, impairment and learning. One issue that arose with this method is that the information returned was simply a large amount to sift through. Therefore, exclusion criteria needed to be more precise in order to avoid information overload. Therefore, the date of the scientific lab and how recent it was became important for deciding whether or not to use a source. Findings were limited to experiments of the last fifteen years, or the beginning of the century. Also, if a lab sought to explain on a highly esoteric level the physical changes that occurred to the brain, it was also excluded. This is due to the fact that the inquiry seeks to explore the psychological effects of brain trauma, and not the rearranging of minute body parts. This effectively cut down the sheer number of articles returned, but the material in the articles were also filled with terms most likely uncommon for everyday use and so more research was needed in order to fully understand the implications and findings of some of the more detailed experiments. Abstracts were read and used to determine whether an experiment contributed information of worth or if the article could be ignored. The chosen articles were then kept and read in more detail to understand them fully. In the end, a total of three sources were kept to be implemented into this research appendix out of over the initial hundreds of articles as they were deemed to have a large potential impact on our design.

Findings:

Fall Height Threshold:

One article investigated how high an infant can fall without suffering an injury that affects their structural integrity. The study looked at infants less than 48 months old who had checked into the hospital following a fall from less than three meters. They then compared these infants to children with skull fractures or intracranial injuries (ICI) and children with minor head injuries. Also noted were the surface of impact, where on the head impact was made, and the height of the fall.  The mean fall height for infants with minor head trauma was found to be significantly lower than those with ICI. For children who fell from a height less than 2 feet, there was no head trauma or ICI found. This height is based on the infant’s head’s center of gravity. Skull fractures were more likely in children older than twelve months who landed on wood surfaces, and made impact with their temporal or occipital region of their skulls. This means an infant that falls from

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less than two feet and doesn’t make impact with their occipital or temporal skull region is significantly less likely to sustain a serious head injury.

Figure 30

Social Functioning:

One article found on Scopus details how the relationship between parent and child is altered following TBI, or traumatic brain injury and the social functioning ability of the infant. There were 130 children between the ages of 18-60 months observed. Some of the children had minor TBI (47), some of the children had no injury (56), and the rest of the children had an orthopedic injury (27). In order to examine the quality of parent-child interaction, the study examined infants 6 months after their initial injury using the Mutually Responsive Orientation (MRO) scale. The MRO rates the dyadic nature of parent-child interactions. Dyadic just means they’re communicating solely with each other, and that if one party in the relationship doesn’t put effort into the relationship, then the communication fails and the social group falls apart. Another standard used to investigate was the Parental Stress Index questionnaire. The study found significant differences between the TBI group of infants and the non-injured children on the MRO. This means that the child’s interactions with their parental figure deteriorated as the infant wasn’t as responsive or put in effort to respond when stimulated.

Adult Cognitive Ability:

The final study used investigated the relationship between infant head trauma and the likelihood of success by measure of how much education they complete. The level of education completed as well as the scores on a cognitive ability test were used to measure the level of success. The data was collected from 130,298 men through the Danish draft board. 6146 had at some point been admitted to the hospital briefly for a concussion. Of these, 406 had suffered two concussions, while 48 had suffered three or more concussions. The study found that as the number of concussions suffered increased, the cognitive ability decreased for the men and that the younger the age at which they suffered the concussion, the greater the negative impact on their cognitive ability and their education level. This means that despite the fact that concussions do not generally show long term effects, there’s still a risk factor for infants sustaining such an injury as it impacts their cognitive potential.

Suggestions For a Design:

Based upon the findings from these studies, the stroller should not have the infant’s head’s center of gravity higher than 2 feet from the ground and that the temporal and occipital lobes be offered some sort of protection from the ground in a potential falling scenario. With these precautions

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taken, the infant shouldn’t suffer a serious intracranial injury or have their cognitive ability decreased by repeated concussions.

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Works Cited

Hughes J, Maguire S, Jones M, Theobald P, Kemp A. Biomechanical characteristics of head

injuries from falls in children younger than 48 months. Archives Of Disease In Childhood [online]. April 2016;101(4):310-315. Accessed November 4, 2016.

Lalonde, G, Bernier, A, Beaudoin, C, Gravel, J, Beauchamp, M.H. Investigating social

functioning after early mild TBI: The quality of parent-child interactions. Journal of Neuropsychology [online]. Accessed November 4, 2016.c

Teasdale T, Frøsig A, Engberg A. Adult cognitive ability and educational level in relation to concussions in childhood and adolescence: A population study of young men. Brain Injury [online]. December 2014;28(13/14):1721-1725. Accessed November 4, 2016.

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Appendix N: Individual Research | Annick Nshuti

Introduction

Why are the strollers that meet the safety standards still associated with accidents?

Safety is such an important part of our everyday life. Have you ever wondered why safety standards are put in place and why are they carefully and regularly kept track of? Well, to me, just a single thought about of standards and safety takes my mind back in time to remember how I spent this past summer. I worked at the Rwanda Bureau of Standards as an internee, and although my job was nothing compared to what everybody else did, that period made think deeper about why every product needs to meet a certain number of standards before it can finally be used. Having spent three months observing people work tirelessly to make sure products are safe for everyday use inevitably affects my perspective as I think about the current strollers’ safety and raises questions in my mind such as whether the current safety standards adequately addresses the safety of a baby stroller and/or whether these safety standards put user scenarios into complete consideration?

The focus of my paper is then if all the products users get from the market have been assessed and have potentially passed the safety standard tests, why are injuries and accidents caused by baby strollers still happening even when the stroller are “standardly safe?” Are there enough safety standard set for baby products? If yes, should then parents be held accountable for all baby products injuries? If no, what’s the implication of the number of stroller accidents that are being currently recorded? At the end of this paper, it should be clear where the error lies in the whole situation and whether there are ways through which the status quo can be profoundly addressed.

Methods:

I developed search terms relevant to my research question and used a thorough inclusion criteria to identify and read through every information that is available on the stroller safety requirements.

Inclusion criteria:

Primary research about stroller safety regulations English Published literature 2010 Onwards The United States

Key words: safety standards, strollers, injuries, regulations, rules

Database: Engineering village, NU libraries, Web Science, Compendex, Google scholar

Interview Experts: Professor Birdwell

Conduct Product dissections. I assessed the hinges and the maneuverability of brakes of an existing stroller in different scenarios.

Results

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How can a stroller be labelled “safe” and still be a cause of injury?

In my point of view and from the research conducted, there is a variety of reasons why baby strollers cause accidents. Some stroller user-scenarios are simply potential sources of stroller-accidents even when the stroller itself has passed the safety standard tests or in other words “safe for use”. I will explain some of them.

The parent is not carefully enough: For example when they leave the harness tightened incorrectly.

The baby is active or vibrant/stubborn: and may loosen or remove the harness The environment is very adverse: On bumpy roads where the stroller’ wheels

might get trapped into the rocks and the user loses control over the stroller.However, there are cases when the accidents result from the product itself, and those are the one I will focus on.

The daily use

Understanding the safety standards of a stroller and determining if each stroller at the market meets them requires not only assessing the safety standards for a stroller, but also a critical analysis of the daily use of this product. Essentially, for a safety standard to be imperative and relevant it must address all hazards in all types of strollers and carriages in all use scenarios. And the fact that the use of a stroller is basically an on-going routine that involves baby an individual that cannot in any way avoid/prevent a possible accident from happening, increases the probability of accidents and injuries that may occur with this baby product.

The manufacture and the product testing

While most of the baby strollers and carriages are manufactured and used in the United States, there are some of these products that are manufactured outside and imported into the country. Federal law that puts in place safety standards necessitates manufacturers and importers to put their products to test to make sure that they meet the consumer product safety requirements. When the products meet safety requirements they are given a written or electronic certificate that accompany them to the market. Testing happens in qualified laboratories.

Types of testing of products manufactured both within the country borders and overseas: ((The user might do this as well) makes to their product's design, to the manufacturing process, or to the source of component parts for the product could affect the product's ability to comply with the applicable children's product standards. This may affect certain safety rules)

Initial certification testing (third party testing): When a person, organization or company who is not the manufacturer offer the requirements evaluation facilities.

Material change: Over the course of their use, products may lose useful components of their safety requirements. For example, a damaged hinge or a broken strap can be unsafe and yet unassumingly ignored by some parents.

Periodic testing: a developed and rarely implement periodic testing plan especially for strollers and baby carriages.

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The market and the long-term use

While I will not largely discuss the impact of stroller’s and baby products’ cost on the parent’s choice, the fact that whether a stroller is affordable or not may limit of the parents’ or guardians’ options. Generally, strollers tend to be expensive especially when that specific stroller is a well-known to be safe or superior in quality than others. The expensiveness of some of these products cause parents to go for cheaper options such as keeping one stroller for future use with future babies, and/or just getting a secondhand stroller that has a reasonable price.

It is, on the other hand sad that the longer an object gets used, the worse it get in terms of how safe it is to use it. This is no exception for strollers. As discussed, cases such as when the stroller is old (same family), or the stroller is bough old (secondhand), or when the stroller is doesn’t meet safety standards when bought new should not be overlooked. It is therefore not entirely wrong to say that some strollers are used for longer than they are manufactured to. And this could be a reasons why strollers labelled “safe” are still associated with daily injuries and accidents.

Another important facet to point out on the long-term use of a stroller is the concept that aspects of safety must adapt in anticipation of developmental stage for a baby. A stroller used for a baby of 6 months can raise issues of safety if used for a four-year old.

Strongly in line with some of reasons I identified, Catherine E. Downs, a former long-time employee of CPSC and a former presider over the preliminary determination panel for the Office of Compliance, points out in an interview:1. The role of consumer misuse of the product2. The inadequacy of warnings and instructions given to foreign manufacturers are the main causes of accidents in safe strollers.

In a brief question and answer session I had with Prof Birdwell about the safety stroller requirements, he clarifies that the safety standards set are for strollers as well as other electronic devices such as cars are bare minimum requirements which might not necessarily comply with the highest safety standards.

Analysis

There are reasons why strollers that meet the safety standards requirements are still associated with accidents. The daily use of baby strollers is naturally an exposure to accidents. It involves a baby and relatively a bigger amount of attention than a person who is occupied with more just one tasking of pushing the stroller would afford.

Furthermore, research shows that only a small percent of the strollers and baby carriages undergo the three types of testing, as of the Federal law of consumer safety. And if research also shows that a considerable number of strollers are made outside the country and may not be meeting the safety standards requirements but still make it to the market, then it is crucial that these products be kept out of the market.

To conclude, this brings a concern that further research could be done on whether products manufactured by foreign importer are meet the quality and safety standards as they should.

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Discussion/Conclusions/Recommendations

Pertaining with the most dangerous problems that are associated with current strollers, our design decisions were shaped by our research in a way that would both address today’s prevalent stroller misuse, increase the safety of a standard stroller and hence its overall maneuverability. One of the biggest aspect of this research that influenced our design decisions, is the fact that there are no sensor strollers on the market, yet sensors in a stroller theoretically seemed capable to address some of the most common accident scenarios in the daily use of a stroller. In addition, to lack of a design like this at the market, and strongly related to safety regulations putting all user-scenarios in consideration, our group’s design was intended to integrate features that would help parents even when they are not paying attention(putting the case of a user not paying attention in consideration) addresses the problem of the parents’ misuse of the products by warning them and alerting them when some hazardous situation such as (tipping over, unbalanced weight) have the probability to occur

One of the reasons why I think the design of my team (that incorporates both an auditory and visual feedback) is going to be relevant and a partial solution to this. One of the other ways to avoid the over-use of the products will be to indicate the period for which the stroller is designed to be used at most, to ensure the highest standards of safety.

The implications of my findings to my project: this is the fact that no matter how safe a stroller is designed to be, it should be of easy maneuverability and not requiring a huge amount of the user’s attention to operate it. My findings are going to influence my team’s design decisions in that we have and will continue to put into consideration the fact that every stroller needs a testing at some point, and also needs to be affordable in its newest state. This is because we don’t want to use expensive objects to make a really expensive stroller. This is a way to avoid problems of going for the option of buying secondhand strollers(cheaper) or using one stroller for longer than it should be used.

Further questions:

How many products are made by foreign importers roughly?

In what ways can the overall minimum safety requirements adequately involve/consider all user-scenarios?

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References

Children’s Product Certificate (CPC) | CPSC.gov. (n.d.). Retrieved December 3, 2016, from

https://www.cpsc.gov/Testing-Certification/Childrens-Product-Certificate-CPC

CPSC Home | CPSC.gov. (n.d.). Retrieved December 3, 2016, from https://www.cpsc.gov/

Periodic Testing | CPSC.gov. (n.d.). Retrieved December 3, 2016, from https://www.cpsc.gov/Business--

Manufacturing/Testing-Certification/Third-Party-Testing/Periodic-Testing/

Regulations.gov - Comment. (n.d.-a). Retrieved December 3, 2016, from

https://www.regulations.gov/document?D=CPSC-2013-0019-0007

Regulations.gov - Comment. (n.d.-b). Retrieved December 3, 2016, from

https://www.regulations.gov/document?D=CPSC-2013-0019-0004

https://www.cpsc.gov/s3fs-public/pdfs/foia_hazrpt.pdf

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Appendix O: Individual Research | Jacob Hechter

Topic:

One of the primary methods of ensuring the safety of children in strollers is the use of restraints, be they harnesses or restraining bars, to hold children in the stroller. Failure and misuse of these restraints presents significant opportunity for injury of children in strollers. This review explores the nature of restraints in baby strollers, their failings, and possible improvements to their design.

Methods:

This literature review was conducted using several databases available to Northwestern University Students. These databases are: Business Source Premier, Family and Social Studies Worldwide, Global Health, Global Health Archive, and Health and Safety Sciences Abstract. The search of these databases all made use of the keywords “baby stroller” and harness “harness”, and made use of at least one of the following keywords: “Injury” or “Design” or “Safety”. The number of articles found in each database for each search were as follows: 1 in Business Source Premier using “safety”, 27 in Family and Social Studies Worldwide using “safety”, 3 in Global Health using “injury” and 2 using “design”, 5 using Global Health Archive and “injury”, and 1 in Health and Safety Sciences Abstracts using “injury”.

This literature review also made use of the publicly available sources from Google Scholar and Google Patents. A search of Google Scholar using the keywords “5-point harness”, “baby”, “Usability”, “Misuse” and “Stroller”, as well as the exclusion criteria “wheelchair”, yielded 51 results. A different search of Google Scholar using the keywords “baby”, “Restraint”, “Usability”, “Misuse” and “Stroller”, as well as the exclusion criteria “wheelchair”, yielded 281 results. A search of Google Patent using the keywords “Baby”, “Stroller”, “restraint”, and 5-point harness yielded 75 results.

Each of the above searches were done with a date range of 2000 to 2016, although a few sources from before that time period were found and used because of the relevance and insight provided. Each search looked for only English language sources, and only published literature was made use of. Many of the results found in the above searches were not used in this literature review because of their lack of relevance and connection to stroller harness or mechanisms.

Results:

Stroller harnesses fall under 3 major categories: The 3-point harness and the 5-point harness. The 3-point harness is a harness anchored to the stroller at either the shoulders (Lerner & Huey, 2001) or the hips (O’Callaghan, 2000), and at the crotch, resulting in 3 anchor points. The 5-point harness is anchored at the shoulders, hips, and at the crotch, resulting in 5 total anchor points(Lerner & Huey, 2001). Both of these types of restraints are recommended, but the five point harness is considered safer (O’Callaghan, 2000), likely because of the more points of contact and the reduce. These harnesses tend towards being made with fabric straps and buckles

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made of “stiff plastic” (Anscher, 2004). Straps around the shoulders and the hips tend to be adjustable, while straps at the crotch tend not to be. Some harness designs tend towards a “roller coaster” design, made with hard, inflexible bars. This design provides the advantage of being very secure and difficult for children to defeat but is also difficult to remove in the case of accidents (“Child restraining seat,” 2015).

Another common kind of restraint is known as a restraint bar. It is a “rigid bar that encircles the child” (Lerner & Huey, 2001) at the front of the seat(“Stroller,” 2010). This provides an area of free movement for the child, but is not usually considered a primary restraint because of that freedom of movement, and because it does not usually contact the child in the same way a harness does. It is a fairly common design, and can be either a permanent or removable feature (Lerner & Huey, 2001)

From 1990 to 2010, an estimated 174,935 stroller related injuries occurred because of falls from a stroller. Falls from strollers were by far the largest by far the largest cause of stroller related injury, consisting of 66.8% percent of the sample (Fowler, Kobe, Roberts, Collins, & McKenzie, 2016). A large portion of these falling cases have occurred because of restraint failure, restraint misuse, or restraint nonuse (Lerner & Huey, 2001).

Restrain Failure

Harnesses can also be designed and tightened in such a manner that they can cause strangulation of children. Because of the cylindrical body shape of infants (Lemer, Huey, & Meiers, 2002), it is possible for infant to slide down the stroller and through one of the holes in the harnesses when it is in the reclined position. Because their head protrudes out from their body, the harness strap can get caught around their neck, and the infant die of strangulation because of this. This is the major cause of infant death in strollers (“Product Hazards - Strollers | Kids In Danger,” n.d.) (Lemer et al., 2002).

Failure of the restraints can simply be due to faulty manufacturing. For example, a stroller was recalled after it was found that a force of as little as 2 pounds could cause the stroller buckle to be released(“Strollers need new buckles,” 2009), making it easy for a child to strain too hard against or for a sudden bump to cause the restraint to become unclipped. Failure of stroller restraints can occur because of three major factors: The child defeats the restraint, the child slips out of the restraint, or the restraints come loose and the child falls out (Lerner & Huey, 2001). These restraints can be also categorized under 6 major action which cause injury due to restraint failure. The child can come to a standing or kneeling position in the stroller, then fall from the stroller. The child can lean over the side of the stroller and either fall, partially fall, or be suspended from the stroller. The child may lean sideways or forwards, resulting in their hands contacting a mechanism of the stroller, such as a wheel or a hinge. The child may lean forward and fall out of the seat, or become entangled in the restraints when they learn forward. Particularly young and small children may slip through leg openings after they have placed both legs in one side of the harness. They also may slide while the stroller is in the reclined position, as mentioned above (Lemer et al., 2002).

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Because of the above restraint failures, there are several design considerations that should be made when designing a stroller seat and harness. The first is that the bodies of children are roughly cylindrical, which makes restraint or rotational movement and preventing sliding difficult. The second is the fact that children can use their thigh bone as a lever, and exert substantial force upon the stroller and/or the restraint. The third is the envelope within a child’s knees and legs can move, as that area can include into the seating compartment if the designer is not careful. Also, children may be able to maneuver both legs into one leg hole of the stroller. The fourth consideration is how the restraint maintains the hip position of the child, as some sort of change in hip position is requires some movement and repositioning of the child’s hips. The fifth consideration Is the containment of the center of gravity. If the range of motion allows the child’s weight to significantly shift the stroller’s center of gravity, if could possibly cause tipping. The final consideration is the design of footholds, as they provide leverage points which a child could use to defeat the restraints (Lerner & Huey, 2001).

Restraint Misuse

Misuse of the stroller restraints and other similar systems is also fairly common. For example, in a study of car seat use, it was found that there were serious and common errors in the adjustment of strap height (the height of the shoulder strap anchors), as well as errors in the amount of slack in the harness. It was common to provide more than 4 finger’s worth (6.35 cm) of slack in the restraints, leaving the child able to shift and possibly escape or defeat the harness(Rudin-Brown, Kumagai, Angel, Iwasa-Madge, & Noy, 2003). In strollers, misuse of the restraints were down to 6 factors, the actions of the child preventing the restraints from being properly adjusted, clothing shifting as a result of the restraint adjustment, poor user feedback for restraint adjustment, a need to keep the restraint loose to provide child comfort and utility, the general difficulty of adjustment, and the difficulty of compensating adjustment for child growth (Lerner & Huey, 2001).

Restrain Nonuse

Many injuries also occur not because the restraints failed for some reason, or because caretakers improperly used them, but because caretakers actually did not make use of the restraints they had been given(“Ovid: 9-1-1 Responses for Shopping Cart and Stroller Injuries.,” n.d.). In one study, during 39% of recorded cases of injury the restraints were not actually being used(Lerner & Huey, 2001). In another study, 52% of reported injuries in related to seating devices like strollers were due to restraint non-use (Beaudin, Maugans, St-Vil, & Falcone Jr., 2013). This lack of use of stroller restraints accounts for a large portion of injuries. Caretakers often do not use these harnesses because of the following factors: A lack of perceived need, the nuisance faced by the parent/caretaker, perceived negative effects on the child, and temporary nonuse for functional acts.

The lack of perceived need stems from a belief that the hazards the harness is supposed to protect against are unlikely, or not very severe, or because they think their child is not prone to behavior that makes lack of restraint use dangerous. They may also believe that they are capable of providing close supervision and stopping incidents when the happen (Lerner & Huey, 2001).

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However, Caretakers also tend to underestimate the ability of young infants to move around in their seats (Beaudin et al., 2013). Children are prone to “reaching behavior” in attempts to interact with their environment, especially when the stroller is stopped and not providing stimulation. This is the kind of behavior that can lead to children losing balance and falling from the stroller (Lerner & Huey, 2001). Only “A few seconds of inattention is sufficient to result in a fall”, despite the presence of the caretaker (Beaudin et al., 2013). This seems to indicate a failure on the part of the caretaker to perceive the danger that the natural behaviors of children can put them themselves in.

Restraint non-use due to nuisance can be due to a couple of factors. Restraints can interfere with activities the caretaker needs to perform on the child, such as cleaning. Operation of the restraints can be frustrating, either because parts are difficult to operate, difficult to reach, or because the restraints easily become entangled. The difficult of operation of the stroller restraints is only magnified by the fact that sometimes they must be operated one handed, while holding the child (Lerner & Huey, 2001). For this reason, some belt designs are spring loaded, so that they retract into a holster when not in use to prevent entanglement and put them in constant, easy to reach places(“Restraint device for children,” 2008). It is also a point in the favor of the roller coaster harness design, which can be quickly and easily locked in place (“Child restraining seat,” 2015).

Some restraint non-use can be due to perceived negative effects on the child. Some children are extremely averse to the use of restraints, causing them to get upset should the restraints actually get put into use. Some restraints, especially if improperly tightened, can cause pain or discomfort. The restraint system may also interfere with the child’s range of movement, and prevent them from being able to perform certain tasks while in the stroller (Lerner & Huey, 2001).

Discussion/Conclusions/Recommendations:

One of the largest problems in stroller injury is because of restraint misuse. Restraint misuse could likely be reduced through simplifying the stroller harnesses and making them generally easier to adjust. This could be done through harness redesigns like the roller coaster style harness, which simply has to be pulled down to secure the child in the seat (“Child restraining seat,” 2015). This does have the advantage of significantly reduced complexity, but it also makes adjustment nearly impossible, which from a consumer and safety standpoint too much of a negative. An easily operable 5-point harness is the optimal solution in this case, and should be the restraint method used in this case. Harness straps should be designed so that they pull out of the way when not in use, either into the stroller or to the sides of the seat. or self-tighten, through the use of springs (“Restraint device for children,” 2008). However, overall, the most important factor is to make use of the 5-point harness.

Stroller restraint non-use is also another major source of injury. This non-use is due to a variety of factors, but overall they seem to stem from false assumptions about what is safe and what is not, the assumption that their children will not engage in behavior that would put them in danger, and the belief that they are able to monitor their child perfectly and stop any sort of

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dangerous behavior. Warnings about the dangers of restraint nonuse should be added to strollers, to inform parents of the dangers of not using the restraints. From the perspective of an organization such as KID, an education campaign undertaken across the country about the danger of stroller restraint nonuse is likely a useful endeavor. On the product scale, “pictoral diagrams have been specifically demonstrated as improving compliance to warnings” (Beaudin et al., 2013), so the addition of such diagrams may reduce restraint non-use. The design ideas described in the previous paragraph would also likely increase restraint use. A feedback mechanism to make parents aware of the fact that harness is undone should also be added.

The 6 design considerations mentioned in the restraint failures should also be given due consideration by future teams when designing the stroller seat and harness system (Lerner & Huey, 2001).

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