Seattle transportation officials say they've synchronized the traffic signals at all 258 downtown intersections for the first time in two...

Seattle transportation officials say they’ve synchronized the traffic signals at all 258 downtown intersections for the first time in two decades.

The lights were reprogrammed to reduce waiting times, especially north-south during busy hours. Other settings were installed to reduce evening delays and to handle sports crowds.

Driving through the downtown corridor between Interstate 5 and Elliott Bay has long been a struggle for drivers.

Years ago, a speed of 30 mph would assure a steady stream of green lights for a driver. But traffic patterns have evolved with the opening of Pacific Place shopping mall, new stadiums, more suburban express buses, and the conversion of Third Avenue to a transit street at peak times. The city hopes to adapt to the changes.

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About 18 months and $300,000 went into the downtown project, funded by the voter-approved “Bridging the Gap” property-tax increase, said Grace Crunican, director of the Seattle Department of Transportation.

Computer models predict an overall 40 percent reduction in wait times, said Brian Kemper, electrical systems manager.

Southbound traffic on Fifth Avenue received higher priority in the afternoon than traffic crossing at Stewart Street and Olive Way. On Third Avenue, signals were combined so a bus should get two or three green lights between stops, Kemper said.

Pressure on downtown streets will increase if the Alaskan Way Viaduct is removed or replaced after 2012.

“We know that the best car trip is the trip that’s not taken, but we all have lives to live, trips that need to be taken,” and better signals should help, Mayor Greg Nickels said.

Crunican said signals will be improved in West Seattle, Fremont and the Rainier Valley over the coming year.

Traffic signals are part of Tim Eyman’s proposed Initiative 985. It would require money collected from red-light cameras, vehicle sales taxes and perhaps some tolls to go into a congestion-relief account — which might go toward signal projects.

“I think everyone has had an experience where they hit a red light every time,” said Eyman.

If Nickels is touting better traffic flows, said Eyman, he ought to welcome some independent oversight by state Auditor Brian Sonntag, who would conduct performance audits if I-985 passes.

Mike Lindblom: 206-515-5631 or