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Mercer East Phase I - Fairview to Dexter Avenue
Project Background
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Mercer West Phase II - Dexter Avenue to Elliott Way W

Mercer East Project Background

The “Mercer Mess” is a major bottleneck in the Seattle area, hindering access to Seattle’s fastest growing neighborhood, South Lake Union. The existing Mercer Street and Valley Street couplet were constructed in the late 1950s as a temporary solution to outdated traffic problems. After more than 40 years of debate, construction is underway from 2010 to 2013.

On February 16, 2010 Seattle was awarded $30 million in federal stimulus. This was the last piece of the puzzle to build improvements including widening Mercer to create a two-way boulevard, reconstructing Valley Street as a local access street, providing new and wider sidewalks, improving connections to transit and adding bicycle lanes. The project replaces major utility infrastructure and integrates many environmentally friendly and sustainable design features. It supports the Alaskan Way Viaduct Replacement Project (SR 99) and rebuilds the street grid in South Lake Union.

The Problem

Current Conditions

  • The “Mercer Mess” has been a regional problem for over 40 years.
    • Circuitous one-way routing slows down traffic and makes the transportation system complicated
    • Over 200 accidents happen each year
  • The corridor cannot handle the 80,000 vehicles each day that use it.
    • Congestion backs up onto Interstate 5 and impacts the entire regional transportation system
    • Limits access to jobs, reduces opportunities for economic growth and slows down trade
    • Vehicle-based design creates barrier and inhibits the use of transit, walking and bicycling
    • Reduces accessibility for persons with disabilities, senior citizens and those who do not drive
  • The public infrastructure in the Mercer Corridor is obsolete and in poor condition
    • Utilities are 80 to 115 years old
    • Pavements, sidewalks and signals are in poor and very poor condition

The Solution

Project Map

Once completed, Mercer St. will have three eastbound lanes traveling onto I-5 (the same number of through lanes to I-5 that Mercer St. has today) in addition to a far right through lane for vehicles traveling to Capitol Hill (same as today) and a new left-turn lane onto Fairview Ave. N.

In addition to improving mobility for over 100,000 persons each day, the Mercer Corridor Project:

  • Creates economic opportunity and access to jobs and businesses
    • Creates 600 direct construction jobs
    • Supports 22,000 new jobs in South Lake Union
    • Improves links to Port facilities, industry and research/development uses
  • Integrates with land-use, creates jobs/housing balance
  • Fixes obsolete public infrastructure up to 115 years old
  • Support Alaskan Way Viaduct and Seawall Replacement Project
  • Improves the environment
    • Reduces energy use
    • Reduces greenhouse gas emissions
    • Improves water quality and tree canopy
  • Supports walking, bike, transit and freight
  • Improves safety, fixing six high accident locations

The Future

Mercer East-Fairview to Dexter design once complete: Valley St. will feature bicycle and pedestrian friendly amenities and reduced vehicle traffic. In addition to the westbound Mercer St. lanes being built, there will be sidewalk improvements and new traffic signals installed along Mercer St.

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