Mayor Announces First Retiming of all Downtown Signals in 21 Years
258 downtown intersections synchronized to improve traffic flow

SEATTLE- Mayor Greg Nickels today announced the completion of a special project that synchronized traffic signals at 258 downtown intersections. This is the first time in 21 years the entire downtown area has been collectively retimed to speed the flow of vehicles.

“By making downtown Seattle’s signals work efficiently, we can help both the city and its motorists,” Nickels said. “This critical work improves travel times, reduces fuel consumption, decreases greenhouse gas emissions, and lessens motorist frustration. The ongoing signal timing effort is a low cost, high impact way to enhance our transportation system and protect the environment.”

The Seattle Department of Transportation (SDOT) optimized the lights from Denny Way to South Jackson Street, and from Alaskan Way to Boren Avenue. The new timing will improve downtown traffic flow with signal cycles designed for rush hours, off-hours, special events and critical incidents like a highway closure. It took SDOT more than 18 months to complete the downtown project at a cost of $300,000.

SDOT’s Traffic Signal Optimization Program enhanced signals at 193 intersections in 2007 and will complete work on at least 150 more this year. In July and August, SDOT will improve signals near Rainier Avenue South, the Fremont/Bridge Way area and West Seattle. Optimization work costs roughly $2,500 per intersection.

After synchronizing the 193 intersections in 2007, travel times improved an average of 40 percent in the morning peak hours, 28 percent in the afternoon peak, and 33 percent in mid-day.

Signal timing is part of the city’s $20 million Intelligent Transportation Systems (ITS) Program which will include in 2009: tripling the number of traffic cameras; increasing roadside message signs from three to 18; rolling out a real-time traveler information map; providing travel times along key arterial routes; offering traffic information for Port of Seattle freight haulers, and introducing computer managed traffic control along First Avenue South, Fourth Avenue South, and Elliott Avenue West based on real-time traffic data.

Map of Optimized Downtown Seattle Signals (PDF format)

Visit the mayor’s web site at www.seattle.gov/mayor. Get the mayor’s inside view on efforts to promote transportation, public safety, economic opportunity and healthy communities by signing up for The Nickels Newsletter at www.seattle.gov/mayor/newsletter_signup.htm.

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Office of the Mayor