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.

2

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