Today, October 18, the Seattle Department of Transportation (SDOT) implemented the newest feature of its Intelligent Transportation System to help manage traffic on city streets. Starting today, travel times appear on dynamic message signs on five key arterial streets during the morning and evening commute periods, from 6 to 9 a.m. and from 3 to 7 p.m., providing drivers with real-time information to help them choose the best route.

Also beginning today, travel times for eight major Seattle corridors are available on the Travelers Information website and on iPhones 24-hours a day, seven days a week. The website and iPhone information enables commuters and truck drivers to find out about traffic conditions before they leave so they can avoid traffic choke points. The travel times posted on dynamic message signs inform drivers who are already on the road of conditions ahead. When drivers choose routes with less congestion, traffic is better distributed among available routes.

There are many components to the Intelligent Transportation System, designed to reduce vehicle delay by 40 percent, travel time by 10 to 25 percent, emissions by 5 to 8 percent, and fuel usage by 10 percent. When the system is completed in March, there will be 22 dynamic information signs, 80 vehicle license detectors (to collect travel times), 130 traffic cameras, solar-energized traffic volume counters, upgraded computer-controlled traffic signal equipment, and fiber optic connections. Traffic signals in three corridors automatically adjust their own timing according to traffic volumes—First Avenue South, Fourth Avenue South, and 15th Avenue West. When bridges open for marine traffic—and close to motor vehicles—traffic signals automatically adjust. Traffic signals in major corridors give priority to emergency vehicles, buses and light rail.

The Traveler’s Information website (www.seattle.gov/travelers) is an important part of the system. In addition to real-time travel times, real-time traffic levels on major city arterials are shown in colors—green, red and black—and views from more than 100 city and state traffic cameras are available. Significant events that affect traffic are listed, such as sports events, construction, and traffic accidents.

SDOT engineers work from a Traffic Management Center where they can monitor traffic and adjust signal timing remotely when necessary due to traffic conditions, and keep the traveling public informed.

The state of Washington, King County, Port of Seattle and federal government, have provided funding and support for the design and installation of the city’s Intelligent Transportation System. The program has initially focused on the corridors that will be most affected by the construction of the Alaskan Way Viaduct replacement—West Seattle, 15th Avenue in Ballard and Interbay, and major arterial streets in the south industrial area. In the future, the system will be expanded to other parts of the city.

For more information: Adiam Emery, (206) 684-5121, adiam.emery@seattle.gov

Media contact: Marybeth Turner, (206) 684-8548, marybeth.turner@seattle.gov