Concurrency and LOS Current Program Assessment City Council - - PowerPoint PPT Presentation

Concurrency and LOS Current Program Assessment

City Council Meeting September 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 the

transportation 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 Intersections and Roundabouts Two-way and all-way Stop-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

• nce 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

• f 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