Date:  Monday, August 16, 2010

Contact: Patty Michaud, WSDOT Communications, 206-716-1133 (Seattle)

SEATTLE – A week after the high-tech traffic signs of Smarter Highways lit up over I-5, traffic engineers at the Washington State Department of Transportation (WSDOT) say the system is working well. The signs automatically alert drivers to slow down for congestion and warn them of blocked lanes ahead.

“It’s exciting to see this technology in place and watch it respond dynamically to traffic on one of our busiest corridors,” said Toll Division Director Craig Stone. “We worked hard to make the signs intuitive, so drivers would know what to do. Drivers are helping by paying attention to the information.”

The electronic signs responded to congestion on Tuesday, Aug. 10, minutes after they were activated. Illuminated LED signs over each lane of the highway adjusted the speed limit to warn drivers as they approached slower midday traffic. The system continues to follow traffic patterns closely, reducing the speed limit as congestion builds and returning to the normal 60-mph speed limit when the backup eases.

“This type of information helps prevent the panic braking that causes collisions,” said Stone. “This section of I-5 has a collision every day on average and we expect Smarter Highways to help reduce that.”

Traffic engineers have used the system several times over the first week to warn drivers approaching blocking incidents on I-5. On Sunday yellow merge arrows over the two right lanes alerted drivers to change lanes, as they approached a blocking incident. A mile up the freeway near Holgate Street, red X’s over the same two lanes indicated both lanes were closed for a medical emergency. Drivers followed the directions and traffic flowed past the incident without sudden braking, last-minute lane changes, stops and collisions.

Activating new technology can be challenging, so WSDOT engineers are monitoring the system 24 hours a day to address any issues as they occur. On the first day of Smarter Highways in action, traffic engineers noticed the variable speed-limit signs changing too quickly in areas where traffic frequently transitioned between flowing at normal speed to slower speeds and congestion. Moving quickly, engineers reduced the system’s sensitivity to vehicle-speed fluctuation and smoothed out the flow of traffic.

“We launched the system in early August because we know it is a traditionally light traffic month,” said Stone. “This quieter traffic period provides drivers and engineers the opportunity to get familiar with the new tool.”

The $23.8 million Smarter Highways project on northbound I-5 is funded as part of the Alaskan Way Viaduct Program. The technology will help keep people and goods moving on I-5 during construction to replace the Alaskan Way Viaduct.

Drivers soon will use Smarter Highways on two other busy corridors:

• SR 520 between I-5 and 130th Avenue NE in Bellevue in fall 2010
• I-90 between I-5 and 150th Avenue SE in Bellevue in spring 2011

To learn more about how WSDOT is making highways smarter, visit: http://www.smarterhighways.com/.

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WSDOT's mission is to keep people, businesses and the economy moving by operating and improving the state's transportation systems. To learn more about what we're doing, go to www.wsdot.wa.gov/news for pictures, videos, news and blogs. Real time traffic information is available at http://www.wsdot.wa.gov/traffic or by dialing 5-1-1.

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