As Bellevue’s growth continues, so do the number of cars on the roads. While planners have worked for years on road projects to add more capacity, the city is also taking steps to make its infrastructure smarter.
The six-year, $4.5 million project allows city crews to install “intelligent” traffic lights in various parts of town. The system, known as Sydney Coordinated Adaptive Traffic System (SCATS), allows traffic engineers at the city to collect data in real time – and then adjust how long lights stay red or green.
The project, which began in 2009, already has such “smart” traffic lights at 69 intersections. When complete, a total of 184 will be upgraded, said Mark Poch, Bellevue’s traffic engineering manager.
“It’s counting cars, just like engineers, except it’s doing it a lot faster than we could ever hope to do it,” Poch said.
Thus far, Bellevue has created smart lights in Factoria, downtown and the Hospital District. Work this year is adding intersections along 148th Avenue from State Route 520 south to Eastgate.
Bellevue is the only city in Washington using such a system, Poch said. Most cities use a signal pattern that changes based on time of day, but without the ability to adapt to traffic minute by minute.
Bellevue officials went around the world to find the system, which was originally developed in Australia, Poch said. The system lets the city improve traffic flow without undergoing as many high-expense road projects, Poch said.
“By systematically improving intersections, without adding concrete, without widening the roads, at that level of cost is really benefiting the city,” he said.
Poch said things are working well so far. Travel time on various routes downtown has decreased according to city figures that measured levels on random days.
The benefits of the system can be seen first hand at Bellevue’s traffic control center in City Hall. Here, information about light schedules sit side by side with traffic cameras on a wall of screens. All major weather events, construction and traffic are monitored, helping engineers and decision makers make the right calls to keep traffic moving.
Fred Liang has been with the city as a signal engineer for 26 years. Every decision he makes with traffic lights comes down to priorities. He has to balance what is best for pedestrians, bicyclists and motorists.
The intelligent traffic lights take some of the burden off him by adjusting to traffic patterns, allowing him to focus on the bigger issues.
“Everybody has an interest,” he said. “We have to make decisions on what is best for each group while still keeping a balance.”
THE PLAN
When the program is complete, Bellevue will have created 184 “intelligent” intersections in Bellevue. The first section was completed in 2010. Phase 2, which was completed in January, finished out the main downtown streets and the Hospital District, while Phase 3 involves 148th Avenue. Phases 4, 5 and 6 will be completed over the next three years. Phase 4, scheduled for completion in 2013, will focus on the main roads in the Bel-Red corridor. Phase 5 will improve lights through South Bellevue, and Phase 6 will fill in some gaps throughout the city, primarily on downtown side streets.
