TRANSPORTATION ELEMENT

I. INTRODUCTION

The intent of the Transportation Element is to provide policies and projects to guide the development of Mercer Island transportation system in support of the City’s vision for the future. The policies guide the actions of the City, as well as the decisions related to individual developments.

The Transportation Element provides an inventory of Mercer Island’s existing transportation system and includes all modes of travel — auto, truck, bicycle, bus, and pedestrian. In addition, a section focuses on the special transportation needs of the Town Center.

Objectives of the Transportation Element

The City of Mercer Island has three main objectives within its Transportation Element:

develop multi-modal goals, policies, programs and projects which support implementation of the Land Use Element of the Comprehensive Plan,

define policies and projects that encourage the safe and efficient development of the transportation system, and

comply with legislative requirements for multi-modal transportation planning.

Washington State’s 1990 Growth Management Act (GMA) outlined specific requirements for the Transportation Element of a city’s comprehensive plan. It calls for a balanced approach to land use and transportation planning to ensure that a city’s transportation system can support expected growth and development. In addition, it mandates that capital facilities funds be adequate to pay for any necessary improvements to the transportation system. Finally, a city must adopt specific standards for the acceptable levels of congestion on its streets; these standards are called level of service (LOS) standards.

At the federal level, transportation funds have been focused on the preservation and improvement of transportation facilities and in creating a multi-modal approach to transportation planning. For Mercer Island, transportation projects that combine improvements for auto, buses, bicycles, and pedestrians have a much greater chance of receiving state and federal grant funds than those that focus solely on widening the road to carry more single-occupant vehicles.

Other legislative requirements addressed by the Transportation Element include the King County 2012 Countywide Planning Policies, the 1991 Commute Trip Reduction Act, the Americans with Disabilities Act (ADA) and the 1990 federal Clean Air Act Amendments. Each of these laws emphasizes closer coordination between a jurisdiction’s land use planning and its approach to transportation planning.

Transportation Today

Most of Mercer Island’s streets are two lane residential streets with low to moderate volumes of traffic. Island Crest Way, a north-south arterial which runs the length of the Island, is an exception to this rule because it is a principal feeder route to I-90. East and West Mercer Way ring the Island and provide two connections with I-90 as well. SE 40th Street and Gallagher Hill Road are also major traffic carriers in the north-central portion of the Island. In addition to arterial streets, the local street network provides access to other streets and private residences and properties. Public transit serves the Park and Ride lot in the I-90 corridor and along Island Crest Way.

Mercer Island has over 56 miles of trails, sidewalks and bicycle lanes for non-motorized travel. A regional trail runs across the north end of the Island along the I-90 corridor providing a convenient connection to Seattle and Bellevue for pedestrians and bicyclists.

Upcoming Changes

Regional changes to the transportation system will likely change how Mercer Island residents travel and live. The I-90 center reversible lanes will be replaced by the Sound Transit East Link light rail line, slated for completion in 2023. A new light rail station at the Town Center will provide access to destinations in Seattle, Bellevue and other cities that are part of the Sound Transit system. In addition, commencing in the summer of 2017, Mercer Island residents will no longer have access to the center reversible lanes, but will instead access new dedicated HOV lanes. The current park and ride at North Mercer Way is frequently at or near capacity, and parking demand will increase when the center HOV lane is closed and with Light Rail. The City should address the overall parking for Mercer Island citizens, the total funding costs, and work with other agencies.

In sum, these regional changes will likely affect travel and land use development patterns, particularly for the north end of the Island. The changes will also provide new opportunities for the Island and will support the vision and development of the Town Center.

Land Use Assumptions – The Comprehensive Plan

Mercer Island’s Comprehensive Plan, of which the Transportation Element is a part, must be internally consistent. This means that the various requirements in each element must not contradict one another. Of particular importance is the relationship between the Transportation Element and the Land Use Element.

The transportation forecasts used in this element are based on Mercer Island growth targets for housing and employment, regional traffic forecasts by the Puget Sound Regional Council, and local traffic counts. Within the 2015 to 2035 planning period, the City’s growth target is 2,320 new housing units and 1,160 new jobs to be generated on the Island during this 20-year period.

The Land Use Element defines Mercer Island’s strategy for managing future growth and physical land development for the next 20 years. Proposed transportation improvements, policies and programs are consistent with the vision of the Land Use Element. The Land Use vision emphasizes continued reinvestment and redevelopment of the Town Center to create a mixed-use pedestrian-friendly and transit-oriented environment. Most of the forecasted housing units and jobs will be located in and around the downtown core. Outside of the Town Center, the lower density residential nature of the remainder of the Island will be maintained with low forecasted changes in household growth.

Town Center Plan

The 1994 Town Center Plan for Mercer Island was updated in 2016 through a cooperative effort of City staff, consultants and many citizens over a two-year long process. Specific goals and policies related to transportation and mobility are in the Land Use element.

The plan for a Sound Transit Link Light Rail station located on the I-90 corridor between 77th Avenue SE and 80th Avenue SE will continue to focus multimodal development and population growth within the Town Center area.

II. TRANSPORTATION GOALS AND POLICIES

The following transportation goals and policies have been developed to guide transportation decisions for Mercer Island. They have been crafted to be consistent with all other Comprehensive Plan elements, including most importantly, the Land Use Element. They also serve to further articulate and implement the City Council’s vision for the future.

GOAL 1:

Encourage the most efficient use of the transportation system through effective management of transportation demand and the transportation system.

1.1Encourage measures to reduce vehicular trips using Transportation Demand Management strategies such as preferential parking for carpools/vanpools, alternative work hours, bicycle parking, and distribution of information and promotion of non-motorized travel, transit and ridesharing options.

1.2Encourage businesses and residential areas to explore opportunities for shared parking and other parking management strategies.

1.3Employ transportation system management (TSM) techniques to improve the efficient operation of the transportation system including, but not limited to: traffic through and turn lanes, management of street parking, signals and other traffic control measures.

GOAL 2:

Receive the maximum value and utility from the City’s investments in the transportation system.

2.1Place a high priority on maintaining the existing transportation facilities and the public rights of way.

2.2Continue to prioritize expenditures in the transportation system recognizing the need to maintain existing transportation assets, meet adopted service level goals, and emphasize continued investments in non-motorized transportation facilities.

2.3Pursue opportunities for private sector participation in the provision, operation and maintenance of the transportation system.

2.4Coordinate street improvement projects with utilities, developers, neighborhoods, and other parties in order to minimize roadway disruptions and maintain pavement integrity.

2.5Explore all available sources for transportation funding, including grants, impact fees and other local options as authorized by the state legislature.

2.6Prioritize transportation investments in the Town Center that promote mixed-use and compact development and provide multi-modal access to regional transit facilities.

GOAL 3:

Minimize negative transportation impacts on the environment.

3.1Use sound design, construction and maintenance methods to minimize negative impacts related to water quality, noise, and neighborhood impacts.

3.2Work with WSDOT and other agencies to minimize impacts on Island facilities and neighborhoods from traffic congestion on regional facilities, implementation of ramp metering, and provision of transit services and facilities.

3.3Construct transportation improvements with sensitivity to existing trees and vegetation.

GOAL 4:

Provide transportation choices for travelers through the provision of a complete range of transportation facilities, and services.

4.1Work with King County Metro, Sound Transit and other providers to ensure adequate transit services to meet the needs of the Island, including:

maintain existing and encourage new public transit service on the Island;

maintain convenient transit connections to regional activity centers, including the Seattle CBD, Bellevue, University of Washington and other centers;

provide convenient transit service for travel on Mercer Island and enhance connections to regional transit stations including the proposed Link light rail station; and

investigate potential new services including demand responsive transit for the general public, subscription bus, or custom bus services.

4.2Provide for and encourage non-motorized travel modes consistent with the Park and Recreation Plan and Pedestrian and Bicycle Facilities Plan.

4.3Support opportunities to facilitate transfers between different travel modes through strategies such as:

providing small park and ride facilities throughout the Island; and

improving pedestrian access to transit with on and off road pedestrian improvements.

4.4 Investigate opportunities for operating, constructing and/or financing park and ride lots for Mercer Island residents only.

4.5Encourage site and building design that promotes pedestrian activity, ridesharing opportunities, and the use of transit.

4.6Promote the development of pedestrian linkages between public and private development and transit in the Town Center District.

4.7Promote the mobility of people and goods through a multi-modal transportation system consistent with the Pedestrian and Bicycle Facilities Plan.

GOAL 5:

Comply with local, regional, state and federal requirements related to transportation.

5.1Comply with the requirements of the federal and state Clean Air Acts, and work with other jurisdictions in the Puget Sound region to achieve conformance with the State Implementation Plan.

5.2Meet the requirements of the Americans with Disabilities Act (ADA) and apply these standards to development of the transportation system.

5.3Comply with the Commute Trip Reduction requirements through the continued implementation of a CTR plan.

5.4Assist regional agencies in the revisions and implementation of the Transportation 2040 (PSRC), WSDOT Highway System Plan, and the 2007-2026 Washington Transportation Plan and subsequent versions of these documents.

5.5Work with the participants of the Eastside Transportation Partnership (ETP) to coordinate transportation planning for the Eastside subarea.

5.6Comply with state initiatives and directives related to climate change and greenhouse gas reduction. Identify implementable actions that improve air quality, reduce air pollutants and promote clean transportation technologies.

GOAL 6:

Ensure coordination between transportation and land use decisions and development.

6.1Ensure compatibility between transportation facilities and services and adjacent land uses, evaluating aspects such as:

potential impacts of transportation on adjacent land use;

potential impacts of land development and activities on transportation facilities and services; and

need for buffering and/or landscaping alongside transportation facilities.

6.2Develop strategies to manage property access along arterial streets in order to preserve their function.

6.3In the project development review process, evaluate transportation implications including:

congestion and level of service;

connectivity of transportation facilities and services from a system perspective;

transit needs for travelers and for transit operators; and

non-motorized facilities and needs.

6.4Ensure that transportation improvements, strategies and actions needed to serve new developments shall be in place at the time new development occurs or be financially committed and scheduled for completion within six years.

6.5As part of a project’s SEPA review, review the project’s impact on transportation and require mitigation of on-site and off-site transportation impacts. The City shall mitigate cumulative impacts of SEPA-exempt projects through implementation of the Transportation Improvement Program.

6.6Develop standards and procedures for measuring the transportation impact of a proposed development and for mitigating impacts.

6.7Participate in the review of development and transportation plans outside the City boundaries that may have an impact on the Island and its transportation system, and consider the effect of the City’s transportation plans on other jurisdictions.

6.8Encourage transit, bicycle and pedestrian principles in the design of projects including:

locating structures on the site in order to facilitate transit and non-motorized travel modes;

placing and managing on-site parking so to encourage travel by modes other than single occupant vehicles;

provision of convenient and attractive facilities for pedestrians and bicyclists; and

provision of public easements for access and linkages to pedestrian, bicycle and transit facilities.

6.9Require adequate parking and other automobile facilities to meet anticipated demand generated by new development.

GOAL 7:

Provide a safe, convenient and reliable transportation system for Mercer Island.

7.1Include in the City’s roadway design standards, requirements for facilities to safely accommodate travel by all travel modes.

7.2Provide a safe transportation system through maintenance and upkeep of transportation facilities.

7.3Monitor the condition and performance of the transportation system to compare growth projections with actual conditions, assess the adequacy of transportation facilities and services, and to identify locations where improvements may become necessary.

7.4Monitor traffic accidents, citizen input/complaints, traffic violations, and traffic volumes to identify and prioritize locations for safety improvements.

7.5Where a need is demonstrated, consider signage, traffic controls, or other strategies to improve the safety of pedestrian crossings.

7.6Verify the policies, criteria and a process to determine when, and under what conditions, private roads and privately maintained roads in the public right of way should be accepted for public maintenance and improvement.

7.7Coordinate with local and regional emergency services to develop priority transportation corridors and develop coordinated strategies to protect and recover from disaster.

GOAL 8:

Preserve adequate levels of accessibility between Mercer Island and the rest of the region.

8.1The I-90 Memorandum of Agreement was amended in 2004. Any future modification to such access for Mercer Island traffic must comply with the terms and conditions of the MOA, as amended.

8.2Continue to recognize I-90 as a highway of statewide significance.

8.3Work with King County Metro and Sound Transit to ensure mobility and adequate levels of transit service linking Mercer Island to the rest of the region.

8.4Work with WSDOT, King County Metro, and the Sound Transit to ensure the provision of adequate Park and Ride capacity for Island residents.

8.5Continue to maintain an effective role in regional transportation planning, decisions-making and implementation of transportation system improvements.

GOAL 9:

Balance the maintenance of quality Island neighborhoods with the needs of the Island’s transportation system.

9.1Strive to the extent possible to minimize traffic impacts to neighborhoods and foster a “pedestrian-friendly” environment.

9.2Address parking overflow impacts on neighborhoods caused by major traffic generators such as schools, businesses, parks, and multifamily developments.

9.3Provide facilities for pedestrians and bicyclists designed in keeping with individual neighborhood characteristics.

9.4Work with King County Metro to provide public transit vehicles and services that are more in scale with the City’s neighborhoods and its local road network.

9.5Maintain comprehensive street design guidelines and standards that determine the appropriate function, capacity, and improvement needs for each street/roadway, while minimizing construction and neighborhood impacts.

GOAL 10:

Maintain acceptable levels of service for transportation facilities and services on Mercer Island.

10.1The City of Mercer Island Level of Service (LOS) at arterial street intersections shall be a minimum of “C” within and adjacent to the Town Center and “D” for all other intersections.

10.2Use the level of service standard to evaluate the performance of the transportation system and guide future system improvements and funding. Emphasize projects and programs that focus on the movement of people and provide alternatives to driving alone.

10.3Implement the following strategy when vehicle capacity or funding is insufficient to maintain the LOS standard: (1) seek additional funding for capacity improvements, (2) explore alternative, lower-cost methods to meet level-of-service standards (e.g., transportation demand management program, bicycle corridor development or other strategies), (3) reduce the types or size of development, (4) restrict development approval, and (5) reevaluate the level of service standard to determine how it might be adjusted to meet land use objectives.

10.4Ensure that the City’s level of service policies are linked to the land use vision and comply with concurrency requirements.

10.5Revise the Transportation Element if the Land Use and/or Capital Facilities Element of the Comprehensive Plan are changed to maintain a balanced and consistent plan.

GOAL 11:

Ensure parking standards support the land use policies of the Comprehensive Plan.

11.1Continue to implement flexible parking requirements for Town Center development based on the type and intensity of the proposed development; site characteristics; likelihood for parking impacts to adjacent uses; opportunities for transit, carpooling and shared parking; and potential for enhancements to the pedestrian environment.

11.2Maintain the current minimum parking requirements of three off-street spaces for single family residences, but may consider future code amendments that, allow for the reduction of one of the spaces, provided that the quality of the environment and the single family neighborhood is maintained.

11.3Support business development in the downtown area by prioritizing on-street parking spaces in the Town Center for short-term parking, and encourage the development of off-street shared parking facilities for long term parking in the Town Center.

GOAL 12:

Promote bicycle and pedestrian networks that safely access and link commercial areas, residential areas, schools, and parks within the City.

12.1Maximize the safety and functionality of the bicycle system by enhancing road shoulders, which are to be distinguished from designated bicycle lanes.

12.2Implement the Pedestrian and Bicycle Facilities Plan to meet existing and anticipated needs for non-motorized transportation. This Plan should be coordinated with other transportation planning efforts and periodically updated.

12.3Study opportunities for use of innovative methods for pedestrians crossing streets, including use of colored and textured pavements within the City.

III. TRANSPORTATION SYSTEM – EXISTING CONDITIONS

This section describes and inventories the current travel patterns and transportation system serving Mercer Island, including land, water and air transportation. Major transportation modes serving Mercer Island include automobiles, non-motorized modes such as walking and biking, and public and school transit.

Travel Patterns - How Mercer Islanders Move About

Mercer Island has relatively high levels of vehicle ownership and personal mobility. Approximately two-thirds of the households on Mercer Island have two or more vehicles, while less than four percent of households have no vehicle at all. Comparing the 2012 American Community Survey (US Census) data with the 2000 US Census data a number of changes are observed.

The percent of Mercer Island residents who commute to work by driving alone has dropped from 76 percent to 71 percent, those who take a bus or carpool to work decreased from 17 percent to 14 percent, and those who work at home increased from 7 percent to 10 percent. The average travel time to work for Mercer Island residents is 20 to 23 minutes, which is below the regional average of 27 minutes.

A November 2013 WSDOT Mercer Island Travel Survey found that 55 percent of commute trips originating on the Island traveled west towards the Seattle and 45 percent traveled east towards Bellevue.

Roadway Network

Mercer Island has over 75 miles of public roads. Interstate 90 runs east-west across the northern end of Mercer Island, providing the only road and transit connection to the rest of the Puget Sound region. Access to the I-90 on-ramps and off-ramps is provided at West Mercer Way, 76th Avenue SE, 77th Avenue SE, 80th Avenue SE, Island Crest Way, and East Mercer Way.

There are a number of changes occurring to the I-90 corridor in preparation for Sound Transit light rail, scheduled for completion in 2023. These include the addition of westbound and eastbound HOV lanes to the I-90 mainline. The reversible HOV lanes down the center lanes of the I-90 facility will become the dedicated rail corridor for Sound Transit light rail.

On the Island, most of the road network is comprised of 2-lane local streets serving the Island’s residential areas. Arterial roadways comprise approximately 25 miles, or one third, of the system. In addition to public roads, there are numerous private roads serving individual neighborhoods and developments on the Island.

Roadways on the Island are classified into different categories according to their purpose and physical characteristics. The categories are:

Principal Arterials carry the highest volumes of traffic and provide the best mobility in the roadway network. These roads generally have higher speed limits, higher traffic volumes, and limit access to adjacent land uses.

Secondary Arterials connect with and augment principal arterials and generally have a higher degree of access to adjacent land, lower traffic volumes and lower travel speeds.

Collector Arterials provide for movement within neighborhoods, connecting to secondary and principal arterials; and typically have low traffic volumes and carry little through traffic.

Local Streets provide for direct access to abutting properties and carry low volumes of traffic at low travel speeds. Local streets are usually not intended for through traffic.

Individual streets are assigned classifications based on several criteria, including the type of travel to be served, the role of the street in the overall street network and transportation system, physical characteristics, traffic characteristics, and adjacent land uses. Based on City Staff recommendations, the City Council periodically reviews and updates the street classification system, its criteria and specific street classification designations.

Figure 1 shows the street functional classifications. Figure 2 shows 2014 roadway features describing the shoulder types and sidewalk locations. Figure 3 shows the number of travel lanes, posted speed limits.

Level of Service Standard

Level of Service (LOS) is a measurement of the quality of traffic flow and congestion at intersections and roadways. LOS is defined by the amount of delay experienced by vehicles traveling through an intersection or on a roadway. LOS is based on an A-F scale with LOS A representing little or no delay to LOS F representing extreme delay.

Under the Growth Management Act, each local jurisdiction is required to establish a minimum threshold of performance for its arterial roadways. Cities use this standard to identify specific actions to maintain the adopted LOS standard. The City of Mercer Island has established its Level of Service standard at intersections of two arterial streets as LOS C within and adjacent to the Town Center and LOS D elsewhere. This standard applies to the operation during either the AM or PM peak periods. The intersection of SE 53rd Place/Island Crest Way, which does not have sufficient volume to warrant a signal, will be exempt from the LOS D standard until traffic volumes increase and signal warrants are met.

To be consistent with the WSDOT standard for Interstate 90 and its ramp intersections, the city will accept a LOS D at those intersections. I-90 is designated as a Highway of Statewide Significance under RCW 47.06.140.

Traffic Operations

For transportation planning purposes, traffic operations are typically analyzed during the busiest hour of the street system, when traffic volumes are at peak levels. On Mercer Island, the peak hour of traffic operations corresponds with the afternoon commute, which typically falls between 4:00 and 6:00 in the afternoon (PM peak hour). Traffic counts were collected at 39 intersections throughout the Island

Selected counts for the AM peak hour were also collected to provide an understanding of the transportation system during the morning commute, which typically peaks between 7:30 AM and 8:30 AM.

Table 1 shows the AM and PM peak hour operations for each of the study intersections. Outside of the Town Center, the analysis shows that during the AM and PM peak hour, all intersections operate at LOS D or better for 2014 conditions, except the intersection of SE 53rd Place/Island Crest Way operates at LOS F during the morning peak hour and at LOS E during the afternoon peak hour.

Within the Town Center, where the LOS C standard applies, the intersection of N Mercer Way/77th Avenue SE operates at LOS E during the morning and afternoon peak hours. Figure 5 shows the 2014 LOS at key intersections during the morning and afternoon peak hours.

Table 1. 2014 Intersection Operations

Intersection

AM Peak Hour

PM Peak Hour

Town Center Intersections (LOS C Standard)

SE 24th St/76th Ave SE

B

B

N Mercer Way/77th Ave SE

E

E

N Mercer Way/Park & Ride/80th Ave SE

B

C

SE 27th St/76th Ave SE

--

B

SE 27th St/77th Ave SE

B

B

SE 27th St/78th Ave SE

A

A

SE 27th St/80th Ave SE

B

B

SE 28th St/78th Ave SE

--

B

SE 28th St/80th Ave SE

--

C

SE 28th St/Island Crest Way

B

C

SE 29th St/77th Ave SE

--

B

SE 29th St/78th Ave SE

--

C

SE 30th St/78th Ave SE

--

C

SE 30th St/80th Ave SE

--

B

SE 30th St/Island Crest Way

--

A

SE 32nd St/78th Ave SE

--

B

WSDOT Intersections (LOS D Standard)

I-90 EB off-ramp/W Mercer Way

B

A

I-90 WB on-ramp/N Mercer Way/76th Ave SE

B

C

I-90 WB off-ramp/N Mercer Way/Island Crest Way

C

D

I-90 EB off-ramp/77th Ave SE

B

B

I-90 EB on-ramp/SE 27th St/Island Crest Way

C

C

I-90 EB on-ramp/SE 36th St/E Mercer Way

A

B

I-90 EB off-ramp/100th Ave SE/E Mercer Way

B

A

I-90 WB ramps/100th Ave SE

B

C

Outside of Town Center Intersections (LOS D) Standard

SE 24th St/W Mercer Way

B

B

SE 24th St/72nd Ave SE

--

B

SE 36th St/N Mercer Way

C

C

SE 40th St/W Mercer Way

--

A

SE 40th St/78th Ave SE

--

B

SE 40th St/Island Crest Way

D

D

SE 40th St/SE Gallagher Hill Rd

C

D

Mercerwood Dr/E Mercer Way

--

B

W Mercer Way/78th Ave SE

--

B

Merrimount Dr/W Mercer Way

--

B

Merrimount Dr/Island Crest Way

--

C

SE 53rd Place/Island Crest Way

F

E

SE 53rd Place/E Mercer Way

--

A

SE 72nd St/W Mercer Way

--

A

SE 68th St/84th Ave SE

C

B

SE 68th St/Island Crest Way

D

C

SE 68th St/E Mercer Way

--

A

Parking

Most parking in the City is provided by off-street parking lots, along residential access streets, or by on-street spaces in select areas of the Town Center.

In 2001, the City implemented a permit parking program for on-street parking in the Town Center in response to overflow conditions at the Mercer Island Park and Ride lot. This program preserves selected public on-street parking spaces for Mercer Island resident use, between the hours of 7:00 AM and 9:00 AM, Monday through Friday. All Mercer Island residents are eligible for a Town Center District permit which will allow them to park on Town Center streets during the specified hours.

An additional permit parking program was developed for residential streets north of the park and ride lot on North Mercer Way. This program only allows residents of the area to park on City streets between 7:00 AM and 4:00 PM, weekdays.

Bicycle and Pedestrian Facilities

Bicycle and pedestrian facilities are a valuable asset for the residents of Mercer Island. These facilities are used for basic transportation, recreation, going to and from schools, and the facilities contribute to our community’s quality of life. In 1996, the City developed a Pedestrian and Bicycle Facilities Plan to provide a network of bicycle and pedestrian facilities. The plan focused on encouraging non-motorized travel and improving the safety of routes near the Island’s elementary schools. Of the 47 projects identified in the plan, 38 of the projects were either fully or partially completed during the first 12 years of the plan.

A 2010 update to the plan included vision and guiding principles, goals and policies, an existing and future network, a list of completed projects, revised facility design standards, and a prioritized list of projects. The plan emphasizes further development of safe routes to schools, completion of missing connections, and application of design guidelines.

A regional trail runs across the north end of the Island along the I-90 corridor providing a convenient connection to Seattle and Bellevue for pedestrians and bicyclists. The majority of streets in the Town Center include sidewalks. In addition, there are sidewalks near schools and select streets. Throughout the Island there are paved and unpaved shoulders and multiuse trails that provide for pedestrian mobility.

The bicycle network is made up of designated bicycle facilities including bicycle lanes and sharrows, and shared non-motorized facilities including shared use pathways, off-road trails, and paved shoulder areas. Figure 2 shows the pedestrian and bicycle facilities on the Island as identified by the Pedestrian and Bicycle Facilities Plan.

Public Transportation

The King County Department of Metropolitan Services (Metro) and the regional transit agency Sound Transit provide public transportation services for Mercer Island and throughout King County. There are four major types of service offered on the Island: local fixed route service, regional express service, custom bus service, and Access service.

Local fixed route service operates on the arterial roadway system, and provides public transit service for most of the Island, connecting residential and activity areas. Transit passengers tend to be “transit dependent” travelers, such as those too young to drive, people unable to drive, or those people who do not have access to a private vehicle.

Regional Express service, which also operates on fixed routes, is oriented toward peak hour commuter trips between Mercer Island and major employment and activity centers off the Island. Express service generally picks up riders at central collection areas such as park and ride lots, and stop less frequently along the route to major destinations. Express service is provided west and east along I-90 into Seattle and Bellevue and is provided by King County Metro and Sound Transit.

Custom bus service includes specially designed routes to serve specific travel markets, such as major employers, private schools, or other special destinations. These services are typically provided during peak commute hours, and operate on fixed routes with limited stops. Custom bus service is currently provided between the Mercer Island Park and Ride and Lakeside School and University Prep in Seattle.

Access Service provides door-to-door transportation to elderly and special needs populations who have limited ability to use public transit. Access covers trips within the King County Metro transit service area.

Figure 4 shows the current transit routes serving the Island. In September 2014, King County Metro reduced bus service throughout its service area due to revenue shortfalls. On Mercer Island, the changes reduced the number of routes from six to two. Other service reductions have affected Mercer Island Park and Ride, which was reduced from ten routes to three King County (201, 204 and 216), and two Sound Transit (550 and 554) routes. Some of the remaining routes were provided with expanded service hours.

Route 201 serves the western portion of Mercer Island providing service from the Mercer Island Park and Ride lot, along 78th Avenue SE, West Mercer Way, East Mercer Way, SE 70th Place, and SE 68th Street to Mercer Village Center. This route operates only on weekdays and has only two morning and one afternoon trips.

Route 204 provides service between the Mercer Island Park and Ride lot and the Mercer Village Center. This route travels on 78th Avenue SE, SE 40th Street, 86th Avenue SE, Island Crest Way, and SE 68th Street to the Mercer Village Center. The route operates every 30-60 minutes from approximately 6:00 AM to 6:00 PM on weekdays.

Park and Ride

The Mercer Island Park and Ride is located north of I-90 on N Mercer Way near Mercer Island’s Town Center. The Park and Ride has 447 spaces and is served by Metro and Sound Transit buses.

Fourth Quarter 2013 Park and Ride Utilization Report prepared by King County, the Mercer Island lot is typically fully occupied during weekdays. A number of the users of this lot do not reside on the Island.

To supplement park and ride capacity on the Island, Metro has leased three private parking lots for use as park and ride lots, located at the Mercer Island Presbyterian Church, Mercer Island United Methodist Church, and at the Mercer Village Center. These lots are described in Table 2. Together, they provide an additional 69 parking spaces for use by Island residents.

School Transportation

The Mercer Island School District (MISD) provides bus transportation for public Kindergarten through 12th grade students on Mercer Island. The MISD operates approximately 40 scheduled bus routes during the morning and afternoon. In addition, the District provides free Orca cards to high school students who live more than one mile from Mercer Island High School and do not have either a parking pass or are not assigned to a district bus.

Rail Services & Facilities

There are no railroad lines or facilities on Mercer Island. In the region, the Burlington Northern Railroad and Union Pacific Railroad companies provide freight rail service between Seattle, Tacoma, Everett, and other areas of Puget Sound, connecting with intrastate, interstate and international rail lines. Amtrak provides scheduled interstate passenger rail service from Seattle to California and Chicago. Major centers in Washington served by these interstate passenger rail routes include Tacoma, Olympia, Vancouver, Everett, Wenatchee, and Spokane.

Table 2: Mercer Island Park and Ride Locations and Capacities

Lot

Location

Capacity

Cars Parked

% Spaces Occupied

Mercer Island Park and Ride

7800 N Mercer Way

447

447

100%

Mercer Island Presbyterian Church

84th Ave SE & SE 37th St.

30

15

50%

United Methodist Church

70th Ave SE & SE 24th St.

18

13

72%

Mercer Village Center

84th Ave SE & SE 68th St.

21

5

24%

Air Transportation

Mercer Island does not have any air transportation facilities or services. Scheduled and chartered passenger and freight air services are provided at Seattle-Tacoma International Airport in SeaTac, and at the King County International Airport in south Seattle.

Water Transportation

Mercer Island does not have any public water transportation services. The City’s public boat launch is on the east side of the Island, off of East Mercer Way, under the East Channel Bridge.

IV. TRANSPORTATION SYSTEM – FUTURE NEEDS

This section describes the future transportation conditions and analysis used to identify future transportation needs and improvements.

Future Travel Demand

The future traffic volumes were forecast for the year 2035 based on the City’s land use and zoning, as well as the housing and employment growth targets, as identified in the King County Buildable Lands (2014) report. More than 70 percent of new households and 76 percent of new jobs are forecasted to occur within the Town Center.

The analysis assumes the opening of the East Link light rail line in 2023, which will result in an additional travel option between the Town Center and regional destinations.

Overall, the traffic growth in the Town Center is forecast to increase by 35 percent between 2014-2035, an annual growth rate of 1.5 percent. Town Center traffic growth was adjusted to reflect the higher potential for pedestrian and transit trips. For areas outside the Town Center, traffic growth is expected to be low with approximately 10 percent growth between 2014-2035, an annual growth rate of 0.5 percent. The resulting forecasted traffic volumes directly reflect the anticipated land use, housing, and employment growth assumptions for the Island.

Baseline Traffic Operations

The 2035 baseline traffic analysis uses the forecasted growth in traffic, planned changes to the regional transportation system, and the roadway and intersection improvements identified in Mercer Island’s 2015-2020 Transportation Improvement Program (TIP).

Results of the 2035 baseline traffic operations analysis shows that seven intersections would operate below the LOS standards by 2035 if improvements are not made to the intersections. In the vicinity of the Town Center, the three intersections of N Mercer Way/77th Avenue SE, SE 27th Street/80th Avenue SE, and SE 28th Street/80th Avenue SE, would operate at LOS D or worse during the either AM or PM peak hours, without improvements Outside of the Town Center the intersection of SE 40th Street/SE Gallagher Hill Road, SE 53rd Place/Island Crest Way and SE 68th Street/Island Crest Way would operate below the LOS D standard during either the AM or PM peak hours, without improvements; The WSDOT intersection at the I-90 eastbound on-ramp/SE 27th St/Island Crest Way intersection would operate at LOS E during 2035 PM peak hour. The City will work with the WSDOT to explore improvements at this intersection.

Figure 7 shows the future baseline traffic operations at the study intersections assuming only improvements identified in the 2015-2020 TIP.

In addition to the baseline projects identified in the City’s 2015-2020 TIP, a future needs analysis developed a list of recommended improvements. The future needs analysis identified select projects from the City’s Pedestrian and Bicycle Plan to improve non-motorized safety and connectivity. Additional roadway and intersection improvement projects were identified based on the operational and safety needs through 2035. Figure 6 shows the recommended transportation projects for the next 20 years. Table 3 provides a map identification, describes the location and details for each of the projects, and estimates a project cost. The table is divided into two main categories of project types:

Non-Motorized Projects – The listed projects include new crosswalk improvements and pedestrian and bicycle facilities. These projects are identified projects from the City’s Pedestrian and Bicycle Plan that connects residential areas to schools, parks, regional transit and other destinations.

Intersection/Road Projects – Roadway projects are those that increase the capacity and safety of an intersection or roadway segment. The projects include the maintenance of existing roadway segments to ensure that the City’s current street system is maintained.

The recommended improvements identify a total of $51.6 million dollars of transportation improvements over the next 20 years. About 78 percent ($40.0 million) of the total is for street preservation and resurfacing projects to maintain the existing street system. Another 9 percent ($4.6 million) is for non-motorized system improvements. About 10 percent ($5.0 million) is for traffic operational improvements at intersections to maintain LOS operations.

With the recommended improvements, the intersection operations will meet the City’s LOS standard for intersection operation and the transportation system will provide a better network for pedestrian and bicycle travel, allowing greater mobility for Island residents. In addition, improvements to regional transportation facilities will accommodate growth in housing and employment, which will to be focused in the Town Center, where residents can be easily served by high capacity transit. Table 4 compares the 2035 intersection study locations with baseline and with the recommended improvements for each of the AM and PM study locations. The baseline improvements include the roadway and intersection improvements identified in Mercer Island’s 2015-2020 Transportation Improvement Program. The recommended improvements are those additional improvements that are needed to meet the City’s LOS standard.

 

Table 3. Recommended Project List 2015-2035

MAP ID

LOCATION

DESCRIPTION

JUSTIFICATION

COST ($)

Non-Motorized Projects (NM)

NM-1

PBF Plan Implementation

Annual funding for non-motorized improvements.

2015-2020 TIP: Project D1.

810,000

NM-2

Safe Routes to School - Biennial

Biennial funding for safety improvements near schools.

Ongoing

100,000

Every other year

 

NM-3

Safe Routes - Madrona Crest (86th Avenue SE) Sidewalk

Sidewalk between SE 38th to SE 39th Street.

2015-2020 TIP: Project D2.

510,000

NM-4

Safe Routes to School - New Elementary School

Pedestrian improvements to support the new elementary school.

2015-2020 TIP: Project D3.

454,000

NM-5

Island Crest Way Crosswalk Enhancement - SE 32nd Street

Add Rectangular Rapid Flashing Beacons (RRFB) at existing pedestrian crossing.

2015-2020 TIP: Project D4.

25,000

NM-6

84th Avenue Path (SE 39th to Upper Luther Burbank Park)

Add a gravel shoulder pedestrian facility.

2015-2020 TIP: Project D5.

70,000

NM-7

East Mercer Way Roadside Shoulders (From 6600 block to south end of E Mercer Way)

Add a shoulder for non-motorized users.

2015-2020 TIP: Project D6.

1,067,400

NM-8

West Mercer Way Roadside Shoulders (7400-8000 Block)

Add a shoulder for non-motorized users.

2015-2020 TIP: Project D7.

417,500

NM-9

West Mercer Way Roadside Shoulders (8000 block to E Mercer Way)

Add a paved shoulder (east side) for non-motorized users.

PBFP

422,400

NM-10

West Mercer Way Roadside Shoulders (6500 to 7400 block)

Add a paved shoulder (east side) for non-motorized users.

PBFP

676,800

NM-11

78th Avenue SE - SE 32nd Street to SE 40th Street

Improve with sidewalks, bicycle lanes/sharrows to connect with the Town Center.

PBFP: Project N16.

1,131,300

Intersection Projects (I) / Road Projects (R)

I-1

SE 24th Street/W Mercer Way

Add southbound left turn pocket (re-channelize).

East Link/Fails to meet LOS Standard

25,000

I-2

77th Avenue SE/N Mercer Way

Traffic signal* or add center receiving lane.

East Link/Fails to meet LOS Standard

820,000

I-3

SE 27th Street/80th Avenue SE

Traffic signal.

East Link/Fails to meet LOS Standard

858,000

I-4

SE 28th Street/80th Avenue SE

Traffic signal.

Fails to meet LOS Standard

854,900

I-5

SE 40th Street/86th Avenue SE

Add westbound and eastbound left turn pockets and dedicated left turn signal phase.

2015-2020 TIP: Project C3.

758,800

I-6

SE 40th Street/Gallagher Hill Road

Add eastbound left turn pocket

Fails to meet LOS Standard

133,900

I-7

SE 53rd Place/Island Crest Way

Traffic signal.

Fails to meet LOS Standard

602,700

I-8

SE 68th Street/Island Crest Way

Traffic Signal/Roundabout*

Fails to meet LOS Standard

982,500

R-1

Street Preservation/Maintenance

Street resurfacing based on PCI rating.

2015-2020 TIP: Projects A1, B1-B2, C1-C10, E1-E3.

40,000,000

*Cost estimate reflects higher cost option of alternative actions.

Total 2015-2035 Projects

51,620,200

Table 4. 2035 Intersection Operations - Baseline and Recommended Improvements

 

2035 AM Peak Hour

2035 PM Peak Hour

Intersection

With Baseline Improvements

With Recommended Improvements

With Baseline Improvements

With Recommended Improvements

Town Center Intersections (LOS C Standard)

SE 24th St/76th Ave SE

--

--

C

C

N Mercer Way/77th Ave SE

F

A

F

A

N Mercer Way/Park & Ride/80th Ave SE

C

C

C

C

SE 27th St/76th Ave SE

--

--

B

B

SE 27th St/77th Ave SE

C

C

C

C

SE 27th St/78th Ave SE

B

B

C

C

SE 27th St/80th Ave SE

E

B

E

C

SE 28th St/78th Ave SE

--

--

C

C

SE 28th St/80th Ave SE

--

--

F

C

SE 28th St/Island Crest Way

B

B

C

C

SE 29th St/77th Ave SE

--

--

B

B

SE 29th St/78th Ave SE

--

--

C

C

SE 30th St/78th Ave SE

--

--

C

C

SE 30th St/80th Ave SE

--

--

B

B

SE 30th St/Island Crest Way

--

--

A

A

SE 32nd St/78th Ave SE

--

--

C

C

WSDOT Intersections (LOS D Standard)

I-90 EB off-ramp/W Mercer Way

B

B

B

B

I-90 WB on-ramp/N Mercer Way/76th Ave SE

C

C

D

D

I-90 WB off-ramp/N Mercer Way/Island Crest Way

C

C

E

E

I-90 EB off-ramp/77th Ave SE

B

B

B

B

I-90 EB on-ramp/SE 27th St/Island Crest Way

C

C

C

C

I-90 EB on-ramp/SE 36th St/E Mercer Way

B

B

B

B

I-90 EB off-ramp/100th Ave SE/E Mercer Way

B

B

A

A

I-90 WB ramps/100th Ave SE

B

B

C

C

Outside of Town Center Intersections (LOS D) Standard

SE 24th St/W Mercer Way

B

B

C

C

SE 24th St/72nd Ave SE

--

--

B

B

SE 36th St/N Mercer Way

C

C

D

D

SE 40th St/W Mercer Way

--

--

A

A

SE 40th St/78th Ave SE

--

--

B

B

SE 40th St/Island Crest Way

D

D

D

D

SE 40th St/SE Gallagher Hill Rd

D

C

E

D

Mercerwood Dr/E Mercer Way

--

--

B

B

W Mercer Way/78th Ave SE

--

--

B

B

Merrimount Dr/W Mercer Way

--

--

B

B

Merrimount Dr/Island Crest Way

--

--

C

C

SE 53rd Place/Island Crest Way

F

B

F

A

SE 53rd Place/E Mercer Way

--

--

A

A

SE 72nd St/W Mercer Way

--

--

A

A

SE 68th St/84th Ave SE

C

C

B

B

SE 68th St/Island Crest Way

F

C

D

A

SE 68th St/E Mercer Way

--

--

B

B

V. FINANCIAL ANALYSIS

Since incorporation in 1960, the City has consistently made (or required through private development) transportation investments that have preceded and accommodated population growth and its associated traffic growth. This strategy has enabled the City to make significant improvements in the community’s neighborhood streets, arterial roads, pavement markings, streets signs, pedestrian, and bicycle facilities.

In recent years, the City has relied on gas tax revenues ($450,000 in 2014) and real estate excise tax ($1,500,000 in 2014) to fund local transportation projects.

In 2014, the City established a Transportation Benefit District that added a $20 per vehicle fee to provide an estimated $350,000 annually to support transportation needs. Combined the City anticipates approximately $2.3 to $2.6 in annual revenues. In 2016, the City adopted transportation impact fees to provide another funding source.

Combined with supplemental federal and state grant funding, Mercer Island has sufficient resources to maintain and improve its transportation system over the next twenty years and will be able to accomplish the following:

Maintain the City’s arterial street system on a twenty year (average) life cycle;

Maintain the City’s residential system on a thirty-five year (average) life cycle.

Maintain, improve and expand the City’s pedestrian/bicycle system over the next twenty years.

Maintain and improve the transportation system to meet the forecasted housing and employment growth targets.

VI. IMPLEMENTATION STRATEGIES

The following actions by the City of Mercer Island and other jurisdictions will be necessary to effectively implement the program and policy elements of this transportation element:

Transportation System - Streets, Transit, Non-Motorized

Develop local neighborhood traffic control plans as necessary to address specific issues.

Develop a program for monitoring transportation adequacy to compare projections to actual conditions and identify locations where improvement may become necessary.

Implement Transportation System Management techniques to control traffic impacts.

Planning - Standards, Policies, Programs

Periodically update the City’s inventory of transportation conditions, functioning level of service and projected levels of service.

Complete the plan for non-motorized transportation improvements consistent with the City’s Comprehensive Plan, including a review of the Pedestrian and Bicycle Facilities Plan and its design standards.

Develop a neighborhood parking program to address parking overflow impacts from schools, businesses, parks and multi-family housing

Revise design standards as necessary to comply with ADA requirements.

Continue to involve the public in transportation planning and decisions.

Develop “transit friendly” design guidelines for project developers to follow.

Develop policies, criteria and a process to determine when, and under what conditions, private roads and privately-maintained roads in public rights of way should be accepted for public maintenance and improvement.

Implement the City’s adopted Commute Trip Reduction program.

Financial Strategies

Secure funding to implement the adopted six-year Transportation Improvement Program.

Actively pursue outside funding sources to pay for adopted transportation improvements and programs.

Transit Planning

Work with Metro to reinstate and improve fixed route transit services. Work with Metro to explore alternative methods of providing service to island residents, such as developing a demand responsive service throughout the Island.

Work with Metro and Sound Transit to site, design and construct high capacity transit and parking facilities consistent with Land Use and Transportation Policies contained in the Comprehensive Plan that will be available for use by Mercer Island residents.

VII. CONSISTENCY WITH OTHER PLANS & REQUIREMENTS

The Growth Management Act of 1990 requires that local comprehensive plans be consistent with plans of adjacent jurisdictions and regional, state and federal plans. Further, there are several other major statutory requirements with which Mercer Island transportation plans must comply. This section briefly discusses the relationship between this Transportation Element and other plans and requirements.

Other Plans

The Transportation Element of the Mercer Island Comprehensive Plan is fully consistent with the following plans:

Mercer Island Comprehensive Plan — The Transportation Element is based on the needs of, and is fully consistent with the Land Use Element.

King County and Multicounty Planning Policies — Mercer Island’s proposed transportation policies are fully consistent with PSRC’s multi-county and King County’s countywide planning policies.

Vision 2040— Vision 2040 builds upon Vision 2020 and Destination 2030 to articulate a coordinated long-range land use and transportation growth strategy for the Puget Sound region. Mercer Island Comprehensive Plan’s Land Use and Transportation Elements supports this strategy by accommodating new growth in the Town Center which is near existing and proposed future transportation improvements along the I-90 corridor.

Metropolitan Transportation Plan — The Puget Sound Regional Council (PSRC) has updated its long-term vision of the future transportation system through the Vision 2040 and Transportation 2040 plans. The Transportation Element is consistent with these plans.

Regional Transit System Plan — Sound Transit’s Regional Transit System Plan (RTP) lays out the Puget Sound region’s plans for constructing and operating a regional high capacity transit system. Both the Land Use and Transportation Elements directly support regional transit service and facilities, and are consistent with the RTP.

Plan Requirements

The Transportation Element of the Mercer Island Comprehensive Plan meets the following regulations and requirements:

Growth Management Act — The Growth Management Act, enacted by the Washington State Legislature in 1990 and amended in 1991, requires urbanized counties and cities in Washington to plan for orderly growth for 20 years into the future. Mercer Island’s Transportation Element conforms to all of the components of a comprehensive transportation element as defined by GMA.

Commute Trip Reduction — In 1991, the Washington State Legislature enacted the Commute Trip Reduction Law which requires implementation of transportation demand management (TDM) programs to reduce work trips. In response to these requirements, Mercer Island has developed its own CTR program to reduce work trips by City employees. There are two other CTR-affected employers on the Island; both have developed CTR programs.

Air Quality Conformity — Amendments to the federal Clean Air Act made in 1990 require Washington and other states to develop a State Implementation Plan (SIP) which will reduce ozone and carbon monoxide air pollutants so that national standards may be attained. The Central Puget Sound area, including King County and Mercer Island, currently meets the federal standards for ozone and carbon monoxide. The area is designated as a carbon monoxide maintenance area, meaning the area has met federal standards, but is required to develop a maintenance plan to reduce mobile sources of pollution.