Concurrency and LOS Current Program Assessment · concurrency program. • A development’s trip...
Transcript of Concurrency and LOS Current Program Assessment · concurrency program. • A development’s trip...
Concurrency and LOS Current Program
Assessment
City Council MeetingSeptember 5, 2017
Discussion Topics
• Project Background & Status• State Guidance for Transportation Planning• City’s LOS Standards• City’s Concurrency Measurement• Advantages & Disadvantages of City’s Program• Next Steps for Concurrency and LOS Reevaluation
Background
Goals for thetransportation master plan
Complete connections for all modes
Supported by the community
Fundable & implementable
• Safe & efficient movement for all people
• Improves mobility and respects community character
• Reconsider how transportation success is defined
• In-depth community conversation
• Creating public buy-in for new priorities and approaches
• Create civic champions for implementation
• Modern concurrency system that forwards mobility objectives
• Flexible impact fee program tailored to plan
• Fiscally sustainable based on prioritized actions
TMP Public Outreach-To-Date
• Pop-up Studios: August 16-19th
• Online presence and priorities mini poll: 360 responses and counting
• September 7th TMP Workshop: 6:30-8:30pm in Council chambers
Mini Poll Preliminary Results: What’s the right balance for Sammamish?
Slight preferences towards:• Reducing commute times over improving local street mobility• Connecting the city’s street network over directing traffic towards
arterials• Relieving vehicular congestion over providing non-motorized
improvements• Supporting more transit options over not doing so
LOS and Concurrency Program
GMA Strategies to Balance Growth with Transportation Performance:
• Level of Service (LOS) standards are set for transportation facilities
• The City’s concurrency program maintains the LOS standards over time
• Impact fees paired with concurrency ensure that “growth pays for growth”
Washington State Growth Management Act (GMA)
• Travel forecasts align with land use assumptions
• Intergovernmental coordination• Define LOS objectives• Projects align with LOS objectives• Ultimate list of projects is financially
realistic
The GMA requires communities to consider the following when updating long-range transportation plans:
Sammamish’s Intersection LOS
Generally accepted measure of driver experience during the peak hour.
• LOS D for intersections that include a Principal Arterial, except in cases where LOS D cannot be obtained with three approach lanes per direction. In these cases, LOS E is considered acceptable.
• LOS C for intersections that include Minor Arterial or Collector roadways.
Intersection LOS
• Delay thresholds for intersections
• Uses standard methods with some divergence from 2010 Highway Capacity Manual (HCM) methodology
TABLE 1 INTERSECTION LOS CRITERIA (AVERAGE DELAY PER VEHICLE)
Level of Service Signalized Intersectionsand Roundabouts
Two-way and all-wayStop-Controlled Intersections
A < 10 < 10
B > 10 to 20 > 10 to 15
C > 20 to 35 > 15 to 25
D > 35 to 55 > 25 to 35
E > 55 to 80 > 35 to 50
F > 80 > 50
Segment Evaluation
Methodology• Segment and Corridor evaluation are guided
by City Policy• Compare average weekday daily traffic
(AWDT) volume to an adopted roadway capacity
• Segment’s daily volume must be less than the segment’s estimated capacity
Segment Evaluation
• Number of lanes• Functional classification
• Principal, minor arterial, collector, neighborhood collector
• Lane width• 10, 11, or 12 foot lanes
• Median or turn lane treatments• Ensures turning vehicles do not impede traffic
flow
Segment Capacity is defined by some fairly traditional metrics such as:
Segment Evaluation
• Shoulders and bike lanes• Increase capacity up to 580 daily vehicles
for every foot of width up to 8 feet
• Non-motorized facilities• Increases person-moving capacity, not
car-carrying capacity
Segment Capacity is also defined by less traditional metrics:
Segment Evaluation
Background assumptions for the LOS AWDT threshold definitions:
Corridor Evaluation
• At the corridor level, concurrency is evaluated by a volume-weighted average of the segments that make up the corridor
• The City has 10 designated corridors as concurrency corridors in the 2015 Comprehensive Plan
• Corridors can pass concurrency even if one or more of the segments along the corridor fail
Current City Concurrency Measurement
• LOS is a baseline for City’s concurrency program.
• A development’s trip generation cannot cause an intersection or corridor to fail the City’s standard once projects in six-year TIP are committed.
• The LOS capacity calculations in a concurrency test take into account what will be constructed in the next six years.
Current City Concurrency Measurement
• Concurrency test uses the City’s traffic demand model to distribute and assign trips and check LOS.
• If the concurrency test passes, the development is certified and transportation impact fees are received by the City
Advantages of the City’s Program
• Volume-to-capacity at the corridor level includes facilities such as sidewalks, bike lanes and parallel trails --incentivizes development of “complete streets.”
• Current intersection and corridor standards result in a low level of existing deficiencies -- more project costs funded by impact fees.
• Program considers peak hour intersection delay, an accepted measure of driver experience.
Disadvantages of the City’s Program
• Non-motorized facilities in the capacity calculation do not connect well to the driver’s experience.
• Weighted average of segments to determine corridor concurrency provides flexibility but could miss key issues on segments.
• The use of daily traffic volumes to calculate segment and corridor performance misses peaking issues that impact commutes.
• The methodology is poorly documented.• The program focuses on arterials and results in prioritizing the
north-south corridors.
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Next Steps
Task Date
Current City LOS and Concurrency Program Review
September 5, 2017 Council Meeting
Explore alternative LOS and concurrency models -best practices review
September 19, 2017 Council Meeting
Concurrency hands-on technical meetings (Oct & Nov) w/Council to identify preferred concurrency approach
October & November, with updates at each Council Meeting
Concurrency and LOS proposals – develop revised program
Now to mid-2018 with regular updates at Council Meetings
Thank you
Questions?
Extra slides
Current City Concurrency Test Steps