TRAFFIC IMPACT ANALYSIS NORTH VILLAGE RESIDENTIAL DEVELOPMENT DOUGLAS, MASSACHUSETTS ·...
Transcript of TRAFFIC IMPACT ANALYSIS NORTH VILLAGE RESIDENTIAL DEVELOPMENT DOUGLAS, MASSACHUSETTS ·...
P ARE Pr o je c t No . 0 71 36 . 00
REPO RT
TRAFFIC IMPACT ANALYSIS
NORTH VILLAGE RESIDENTIAL DEVELOPMENT
DOUGLAS, MASSACHUSETTS
Proponent: Heritage Design Group
One Main Street Whitinsville, MA 01588
Prepared By: Pare Corporation
8 Blackstone Valley Place Lincoln, RI 02865
Submitted March 7, 2008 Revised November 14, 2008
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TABLE OF CONTENTS
DESCRIPTION PAGE
INTRODUCTION 1
DATA COLLECTION 1
EXISTING ROADWAY CONDITIONS 5
North Street and Gilboa Street 5
North Street and Pond Street 6
North Street and Gilboa Court 6
Whitins Road/Hough Road and Barnett Road 6
EXISTING TRAFFIC VOLUMES 7
SAFETY ANALYSIS 10
Crash Data 10
Speed Data 10
Stopping Sight Distance 11
Intersection Sight Distance 12
FUTURE CONDITIONS 12
Background Growth 13
Anticipated Development 13
2012 BUILD CONDITIONS 16
Trip Generation 16
Trip Distribution 17
CAPACITY ANALYSIS EXISTING AND FUTURE BUILD CONDITIONS 17
Intersections 18
CONCLUSIONS 22
Figures Figure 1: Locus Map 3
Figure 2: Conceptual Site Plan 4
Figure 3: 2007 AM Peak Existing Volumes 8
Figure 4: 2007 PM Peak Existing Volumes 9
Figure 5: 2012 AM Future No Build Volumes 14
Figure 6: 2012 PM Peak Future No Build Volumes 15
Figure 7: 2012 AM Future Build Flow Chart 20
Figure 8: 2012 PM Future Build Flow Chart 21
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TABLE OF CONTENTS
DESCRIPTION PAGE
Tables Table 1: Spot Speed Results for North Street 11
Table 2: Trip Generation Summary 16
Table 3: LOS Criteria for Unsignalized Intersections 17
APPENDICES
Appendix A Traffic Counts Appendix B Safety Data
Appendix C Trip Generation & Distribution
Appendix D Traffic Capacity Analysis
Appendix E Level of Service Tables
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INTRODUCTION
Pare Corporation (PARE) was retained by Heritage Design Group to perform a traffic impact
analysis for the proposed North Village Residential Development located on North Street in
Douglas, Massachusetts. The development is proposed to include two separate sections: 105
residential condominiums/townhouses and 28 single family detached houses. A separate access
for each section of the development is proposed on North Street between Brown Road and
Colonial Road. Brown Road represents the town line between Douglas and Sutton,
Massachusetts.
Included in this report are existing conditions in the vicinity of the project site, a safety analysis
of the study area, an analysis of the anticipated traffic based on existing 2007, future 2012 no-
build and future 2012 build conditions, and proposed mitigation measures, if required. Existing
2007 conditions represent current conditions based on recent traffic counts and future 2012 no-
build conditions include trips generated by an increase in growth expected in the area without the
construction of the development. The future 2012 build condition represents the future 2012 no-
build condition plus the traffic expected to be generated by the proposed development. A locus
map of the study area is provided in Figure 1 and a conceptual plan for the site is provided in
Figure 2.
DATA COLLECTION
Manual turning movement counts were completed at all study area intersections on Wednesday,
November 14, 2007 and Thursday, November 15, 2007 between the hours of 6:00 to 9:00 a.m.
and 4:00 to 6:30 p.m. Time periods were selected to coincide with the hours of peak traffic and
peak commuter traffic. The volumes obtained were used in the capacity analysis at the
intersections. The study area intersections counted included the following:
• North Street/Gilboa Street (Douglas, MA)
• North Street/Pond Street and Gilboa Court (Douglas, MA) – Two separate 3-way
intersections
• Whitins Road/ Hough Road and Barnett Road (Sutton, MA)
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Brown Street is also located within the study area, but has only two residential properties. Due to
the low volume of vehicles utilizing Brown Street, no traffic counts where perform at the
intersection of North Street and Brown Street. A copy of the traffic count data is provided in
Appendix A.
Automatic traffic recorder (ATR) counts were completed by DATA, Inc. from Wednesday,
December 5, 2007 to Thursday December 6, 2007 on North Street within the project area. Copies
of the ATR count data are provided in Appendix A.
Crash data was requested from the Town of Sutton Police Department and The Town of Douglas
Police Department on November 9, 2007 and was received on November 23, 2007. Additional
crash data was requested and received from the Massachusetts Highway Department
(MassHighway) on November 9, 2007. A copy of the data requests and tables summarizing the
data received are provided in Appendix B.
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EXISTING ROADWAY CONDITIONS
This section describes the roadway network in the study area, surrounding the proposed project.
Land uses surrounding the project site are primarily residential uses. Included in the study area
for North Village Residential Development are four existing unsignalized intersections and the
two proposed access roads to the development. The intersections investigated include:
• North Street/Gilboa Street (Douglas, MA)
• North Street/Pond Street (Douglas, MA)
• North Street/Gilboa Court (Douglas, MA)
• Whitins Road/Hough Road & Barnett Road (Sutton, MA)
A field review of the entire study area was conducted, with field observations recorded at critical
intersections. In addition to the existing intersections, the proposed locations of the site entrances
were also investigated. A description of each intersection is provided below.
North Street and Gilboa Street
The intersection of North Street and Gilboa Street is a four-legged unsignalized intersection
located south of the proposed project site. North Street runs in a north/south direction and Gilboa
Street runs in an east/west direction. Gilboa Street provides direct access to Route 146 east of the
intersection. The northbound approach to the intersection, on North Street, has one 13-foot lane
northbound with one 12-foot lane southbound. The southbound approach to the intersection has
one 18-foot lane northbound with one 12-foot lane southbound. The eastbound approach to the
intersection, on Gilboa Street has one 13-foot lane westbound with one 14-foot lane eastbound.
The westbound approach to the intersection has one15-foot lane on both directions. Directional
traffic at this intersection is separated by a solid double yellow line. The posted speed limit on
North Street is 25 miles per hour and the posted speed limit on Gilboa Street is 25 miles per hour.
Crosswalks are marked across the eastbound and southbound approach to the intersection. This
intersection is 3-way stopped controlled, with the westbound approach operating uncontrolled.
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North Street and Pond Street
The intersection of North Street with Pond Street forms a three-legged unsignalized intersection
located south of the proposed project site. North Street runs in a north/south direction and Pond
Street runs in an east/west direction. Both roadways carry two-way traffic. The northbound and
southbound approaches to the intersection, North Street, have one 11-foot lane northbound with
one 12-foot lane southbound. Directional traffic on these approaches is separated by a solid
double yellow line. The eastbound approach to the intersection on Pond Street is approximately
24 feet wide and is stop controlled at the intersection. The northbound and southbound
approaches operate with no controls. The posted speed limit on North Street is 25 miles per hour,
while Pond Street has no posted speed limit.
North Street and Gilboa Court
The intersection of North Street with Gilboa Court forms a three-legged unsignalized intersection
located south of the proposed project site. North Street runs in a north/south direction and Gilboa
Court runs in an east/west direction. Both roadways carry two-way traffic. The northbound and
southbound approaches to the intersection, North Street, have one 12-foot lane northbound with
one 11-foot lane southbound. Directional traffic on these approaches is separated by a solid
double yellow line. The westbound approach to the intersection on Gilboa Court is
approximately 17 feet wide and is stop controlled at the intersection. The northbound and
southbound approaches operate with no controls. The posted speed limit on North Street is 25
miles per hour, Gilboa Court has no posted speed limit.
North Street at the Proposed Site Driveways
In the area of the proposed site driveways, North Street is a meandering, moderately-hilly
roadway. The approximate roadway width at the northern site entrance is 18 feet, while the
approximate roadway width at the southern site entrance is 20 feet. At both locations, the
roadway is striped with a solid double yellow centerline, and no sidewalks or curbing are present.
Residential driveways are located along the length of North Street, however, their frequency is
greater south of the proposed site. North of the proposed site towards Sutton, fewer driveways
are located, with the houses having increased frontage on North Street.
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Whitins Road/Hough Road and Barnett Road
The intersection of Whitins Road with Hough Road and Barnett Road forms a four-legged
unsignalized intersection located north of the proposed project site. The eastbound approach to
the intersection, Whitins Road has one 17-foot lane westbound with one 14-foot lane eastbound.
The westbound approach to the intersection has one 13-foot lane westbound with one 14-foot lane
eastbound. Directional traffic on this approach is separated by a solid double yellow line. The
northbound approach to the intersection, on Hough Road, is generally 26 feet wide and is stop
controlled at the intersection. The southbound approach to the intersection, on Barnett Road, is
generally 27 feet wide and is stop controlled at the intersection. The eastbound and westbound
approaches operate with no control. Both the Sutton Senior Center and Town recreational fields
are located along Hough Road north of the proposed site and south of Whitins Road. The posted
speed limit on Whitins Road is 35 miles per hour.
EXISTING TRAFFIC VOLUMES
Based on the traffic counts completed, the peak hours of the roadway network were determined to
occur from 7:00 to 8:00 a.m. and 4:15 to 5:15 p.m. on a typical weekday. The existing peak hour
volumes are shown in Figures 3 and 4.
Automatic traffic recorder (ATR) counts conducted over a 24-hour period from Wednesday,
December 5, 2007 to Thursday December 6, 2007 on North Street provide additional existing
traffic volume data for the study area. North Street on a typical weekday carries approximately
931 vehicles. Based on the MassHighway 2007 Weekday Seasonal Factors for Urban Arterials
and Collectors, the ADT for the roadway is expected to be approximately 960 vehicles per day.
The typical weekday split between the northbound and southbound directions is approximately
54% southbound and 46% northbound. Complete ATR count data and Mass Highway Seasonal
Factors are provided in Appendix A.
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SAFETY ANALYSIS
The roadway network surrounding the proposed site area was analyzed with respect to crash
history and sight distance to determine potential crash patterns and roadway deficiencies. .
Crash Data
To identify potential crash patterns and roadway deficiencies, crash data for the most recent
three-year period was requested from the Town of Sutton Police Department, Town of Douglas
Police Department and the Massachusetts Highway Department (MassHighway) for the entire
study area. A summary of the data received is summarized in Appendix B. A review of the
accident reports indicates that the crash rates calculated at the study area intersections are less
than the MassHighway statewide and District 3 average crash rates. A total of 12 crashes were
reported at the unsignalized intersections between 2004 and September 2007 that could be located
based on the information provided.
Three of the crashes reported at the intersections were rear end crashes, seven were broadside,
and two were loss of control. Rear end collisions often occur at intersections and are typically the
result of driver inattention. The loss of control was due to snow conditions. Most of the
broadside crashes were result of drivers failing to stop at stop sign and most occurred at the
intersection of North Street and Gilboa Street. This four-legged intersection is stopped controlled
on three of the approaches northbound, southbound and eastbound. The westbound approach is a
free movement with no stop control. It is a possibility that some motorists approaching the
intersection may think that all four legs of the intersection are stop controlled, creating confusion.
Placing an additional stop sign on Gilboa Street eastbound approach may safely improve the
intersection. All twelve crashes involved property damage only, with no reported injuries. The
severity and frequency of crashes in the study area does not indicate a significant safety problem.
Based on this, no improvement is recommended to reduce the number of future accidents.
Speed Data
A speed study was conducted on North Street within the study area to determine average travel
speeds and the appropriate design speeds on the roadway. Data was recorded by DATA, Inc. on
Wednesday, December 5, 2007. The results are shown in Appendix A and summarized in the
table below.
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Table 1: Spot Speed Results for North Street
Posted Speed
Average Speed
True Median
(50th Percentile)
85th Percentile
10 MPH
Pace
Percent of vehicles over
25 MPH
Northbound 25 30 32 38 26-35 79
Southbound 25 35 37 42 31-40 87
Speeds were recorded for 430 cars in the northbound direction and 501 cars in the southbound
direction. The posted speed limit on North Street is 25 miles per hour. Northbound on North
Street, the average speed measured was 30 miles per hour, with an 85th percentile speed of 38
miles per hour. Of the 430 cars observed, 79 percent had speeds over 25 miles per hour.
Southbound on North Street, the average speed measured was 35 miles per hour, with an 85th
percentile speed of 42 miles per hour. Of the 501 cars observed, 87 percent had speeds over 25
miles per hour.
Given the current travel speeds on North Street, it is recommended that intersection warning signs
be posted on the roadway in both directions in advance of the proposed site driveways. These
signs will warn motorists of the increased likelihood of entering traffic and potentially slow travel
speeds along the roadway. In addition, centerline striping on the roadway in Sutton would help
delineate the travel lanes for motorists.
Stopping Sight Distance
Stopping sight distance is the distance required for a vehicle traveling at or near the design speed
to stop before reaching a stationary object in its path. Sight distance measurements were recorded
at the two proposed site entrances on North Street. Based on the spot speed study performed,
design speed of 45 miles per hour southbound and 40 miles per hour northbound were selected.
At the proposed single-family housing site entrance on North Street, the stopping sight distance
measured was over 600 feet to the north and 375 feet to the south. This site entrance has an
approximate 8% downhill grade to the north and an approximate 6% uphill grade to the south.
Based on the design speed selected and the roadway grades, the stopping sight distance required
by the American Association of State Highway Transportation Officials (AASHTO) publication
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A Policy on the Geometric Design of Highways and Streets, 2004 for a downhill grade of 6% is
333 feet, for an uphill grade of 9% is 320 feet, and for an uphill grade of 6% is 331 feet. The
stopping sight distances available in both directions exceed the AASHTO requirements.
At the proposed town house site entrance on North Street, the stopping sight distance measured
was 380 feet to the north and over 600 feet to the south. This site entrance has an approximate
2% uphill grade to the north and an approximate 4% downhill grade to the south. Based on the
design speed selected and the roadway grades, the stopping sight distance required by AASHTO
is 344 feet for a 3% uphill grade, and 378 feet for a 3% downhill grade. The available stopping
sight distance in both directions exceeds the AASHTO requirements.
Intersection Sight Distance
Intersection sight distance is the distance required for a vehicle on the major road to reduce speed
to no less than 70 percent of their initial speed due to entering traffic. Intersection sight distance
was measured at a minimum distance of 14.5 feet from the edge of the major road utilizing the
departure sight triangle in each direction
At the proposed single-family housing site entrance on North Street, the intersection sight
distance measured was over 460 feet for left turns from the site entrance and 600 feet for right
turns from the site entrance. Based on the design speed selected, the intersection sight distance
required by (AASHTO) is 500 feet for left turns from minor road and 430 feet right turn from
minor road. Based on the design speed selected the available intersection sight distance for the
left turn from the site entrance exceeds the AASHTO requirement. The right turn from the site
entrance the available sight distance does not meet the AASHTO requirements for design speed
of 45 mph due to roadway vertical alignment. The available intersection sigh distance for this
condition does, however, exceed the AASHTO requirement for a design speed of 40 mph, 2 mph
greater than the northbound 85th percentile speed.
At the proposed town house site entrance, the intersection sight distance measured was 600 feet
for left turns from the site entrance and over 455 feet for right turns from the site entrance. Based
on the design speed selected, the intersection sight distance required by (AASHTO) is 500 feet
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for left turn from minor road and 430 feet right turn from minor road. Based on the design speed
selected, the available intersection sight distance for the left and right turns from the site entrance
exceeds the AASHTO requirements.
FUTURE CONDITIONS
The “no-build” condition is the future year condition that is expected regardless of the
construction of the North Village Residential Development. The development of the future “no-
build” condition involves the projection of existing traffic volumes over a specific time period
and the inclusion of anticipated trips from other planned or proposed developments in the study
area.
Background Growth
To determine the appropriate background growth within the vicinity of the project, the existing
traffic volumes were projected from 2007 to 2012 utilizing a 2.0% per year growth factor
calculated using Douglas MA Census data. The five-year period is the standard required by
MassHighway in their Guidelines for EIR/EIS Traffic Impact Assessments. This growth rate was
applied to the existing turning movements volumes to provide a year 2012 no-build turning
volumes.
Anticipated Development
The Town of Douglas and Sutton Planning Departments were contacted to determine projects
planned within the surrounding area that should be accounted for in the future no-build analysis.
No schedule development or roadway improvements are scheduled under near-term conditions;
thus, no major changes in traffic patterns are forecast.
The addition of the background growth and the 2007 existing traffic volumes results in the
formation of the future 2012 no-build traffic volumes. Figures 5 and 6 provide the future 2010
no-build volumes for the a.m. and p.m. peak hours.
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2012 BUILD CONDITIONS
The future 2012 build condition represents the future 2012 no-build condition plus the traffic
expected to be generated by the proposed development. The future 2012 no-build peak hour a.m.
and p.m. traffic volumes are shown on Figures 7 and 8.
Trip Generation
The proposed North Village Development includes two separate parts: 105 residential
townhouses and 28 single family houses. Access for both parts of the development is proposed on
North Street. To determine the number of trips anticipated with the development, the Institute of
Transportation Engineers (ITE) Trip Generation, 7th Edition, was utilized. A summary of the
anticipated trips is presented in Table 2.
Trip generation for the proposed Residential Townhouses was completed with Land Use Code
230, Residential Condominium/Townhouse. The calculations were performed based on the
weekday a.m. and p.m. peak hours of adjacent street traffic. Using the rates provided the
proposed townhouse development is expected to generate 54 new trips, 9 entering and 45 exiting,
during the a.m. peak hour, and 63 new trips, 42 entering and 21 exiting, during the weekday p.m.
peak hour. The single-family houses were analyzed using Land Use Code 210, Single-Family
Detached Housing. Using the rates provided, the proposed single-family development is
expected to generate 29 new trips, 7 entering and 22 exiting, during the a.m. peak hour, and 34
new trips, 21 entering and 13 exiting, during the weekday p.m. peak hour.
Table 2: Trip Generation Summary
Time Period Residential Townhouse
Single-Family Housing
Total New Site-Generated Trips
Entering 9 7 16 Weekday AM Peak (vph) Exiting 45 22 64
Total 54 29 80
Entering 42 21 63 Weekday PM Peak (vph) Exiting 21 13 34
Total 63
34 97
Complete trip generation calculations are provided in Appendix C.
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Trip Distribution
New trips anticipated to enter and exit the proposed development were distributed based on existing
travel patterns on the roadways adjacent to the development. Both entrances and exit to the
developments are located on North Street, By Evaluating the northbound and southbound existing
traffic volumes on North Street it was determine that during the a.m. peak hour, 68% of the traffic
will enter and exit the site northbound and 32% enter and exit the site southbound. During the
p.m. peak hour, 34% of the traffic will enter and exit the site northbound and 66% will enter and
exit southbound. Complete trip distribution calculations are provided in Appendix C.
CAPACITY ANALYSIS – EXISTING AND FUTURE BUILD CONDITIONS
Capacity analysis was completed for all study intersections for existing, future 2012 no-build, and
future 2012 build. Capacity analysis characterizes intersections based on their level of service
(LOS). LOS is a quality measure describing operational conditions within a traffic stream,
generally in terms of service measures such as speed, travel times, traffic interruptions, etc. Six
LOS are defined for each type of facility, from A to F, with A representing the best operating
conditions and F representing the worst operating conditions. The criteria for unsignalized
intersections is provided below.
Table 3: LOS Criteria for Unsignalized Intersections
Unsignalized Intersection
LOS Delay Time (sec/veh)
A 0-10
B > 10-15
C > 15-25
D > 25-35
E > 35-50
F > 50
Intersection operations and level of service were evaluated for the weekday a.m., afternoon, and
p.m. peak hours at the study area intersections using the latest version of the Highway Capacity
Software (HCS+).
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Intersections
Capacity analysis for a.m. and p.m. peak hours was completed for the following intersections:
• North Street/Gilboa Street (Douglas, MA)
• North Street/Pond Street (Douglas, MA)
• North Street/Gilboa Court (Douglas, MA)
• North Street/Townhouse Site Entrance (Douglas, MA - Future Build Condition Only)
• North Street/Single-Family Housing Site Entrance (Douglas, MA – Future Build Condition
Only)
• Whitins Road/Hough Street w/Barnett Road (Sutton, MA)
Under existing conditions, the intersections of North Street with Pond Street, North Street with
Gilboa Court, and Whitins Road with Hough Road operate at LOS B or better during the a.m. and
p.m. peak hours. Under both the future no-build and future build 2012 conditions, the LOS at
these intersections remains a LOS B or better, with delay times less than 14 seconds per vehicle.
The analysis of the intersection of North Street and Gilboa Street presents a unique challenge due
to the unconventional configuration of the intersection. This intersection currently operates as a
3-way stop-controlled intersection, with the westbound approach operating unopposed. The
methodology of the Highway Capacity Manual does not address this unusual configuration;
therefore, the intersection could not be accurately modeled. To approximate the operation of this
location, the intersection was analyzed as a 4-way stop-controlled intersection with the
understanding that delays for the westbound approach would be erroneous. What this analysis
does reflect, however, is that the impact on the operation of the northbound, southbound, and
eastbound approaches as a result of the proposed development will be minimal.
Under existing conditions, during the a.m. peak hour, the North Street intersection with Gilboa
Street operates at an overall LOS C with approximately 16 seconds of delay per vehicle. Under the
future no-build 2012 conditions, the operation of the northbound approach decreases to LOS D,
with just over 28 seconds of delay per vehicle. The LOS of the other approaches remains
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unchanged, as does the overall intersection LOS. The addition of the anticipated site traffic has no
impact on intersection LOS, and results in just over 23 seconds of delay per vehicle.
During the p.m. peak hour, the intersection of North Street and Gilboa Street currently operates at a
LOS F with approximately 59 seconds of delay per vehicle when modeled as a 4-way stop. The
northbound, southbound, and eastbound approaches to the intersection operate at LOS C or better,
with less than 17 seconds of delay. The westbound approach to the intersection operates at LOS F
with 92 seconds of delay per vehicle. The addition of future no-build 2012 traffic will increase
delay on all approaches. The northbound, southbound, and eastbound approaches to the intersection
will remain at LOS C or better, with less than 19 seconds of delay per vehicle. The westbound
approach continues to operate at LOS F with increased delay times. Under future build 2012
conditions, the LOS will remain unchanged after the addition of the site-generated traffic, with
delay increases of less than two seconds on the northbound, southbound, and eastbound approaches.
The intersections of the proposed development site entrances with North Street are expected to
operate at LOS A or better with less than 9 seconds of delay per vehicle under future 2012 build
conditions during both the a.m. and p.m. peak hours.
Capacity analysis results are provided in Appendix D and level of service tables are provided in
Appendix E.
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CONCLUSIONS
The stopping sight distance for traffic exiting the development from both proposed site entrances
is adequate the selected design speed and the existing roadway grades. The available intersection
sight distance for the townhouse site entrance and the right turns out of the single-family housing
entrance exceed the AASHTO requirements. Intersection sight distance available for the left
turns from the single-family housing entrance does not meet the AASHTO requirement for the
selected design speed but it exceeds the requirement for the 85th percentile speed and the posted
speed limit.
Given the current travel speeds on North Street, it is recommended that intersection warning signs
be posted on the roadway in both directions in advance of the proposed site driveways. These
signs will warn motorists of the increased likelihood of entering traffic and potentially slow travel
speeds along the roadway. In addition, centerline striping on the roadway in Sutton would help
delineate the travel lanes for motorists.
The overall results of this traffic impact analysis indicate that the additional traffic anticipated
with the construction of the proposed North Village Residential Development will have minimal
impacts on the intersections within the study area. With the exception of the North Street/Gilboa
Street intersection, minimal changes in LOS and delay at the study area intersections can be
expected. The capacity analysis results for the North Street/Gilboa Street intersection do not
accurately represent existing or proposed conditions, as there is no available methodology to
analyze a 3-way stop controlled intersection. The volume of traffic expected to be added to this
intersection is minor, therefore, significant impacts to the intersection operations are not
anticipated. Changes in LOS and delay at the intersections are greater as a result of the
background traffic growth than as a result of the proposed development.