The city of Federal Way is looking at ways to improve traffic flow at busy intersections throughout the city.
In the next year, city officials hope to put an adaptive signal control system in place, said Desireé Winkler, the city’s deputy Public Works director and street systems manager.
“It’s a computer system that can take in real-time information for the traffic signals out in the field,” Winkler said. “It will tell you how many vehicles per hour are in each lane. It will tell you how many vehicles are able to make it through a green light each time as traffic is starting to back up.”
The data the system receives is used to adjust the signal timing based on algorithms.
Currently, the city can set time-of-day signal plans, which allow signals to run a specific amount of time based on the time of day.
“We do our best to try to accommodate that peak time,” Winkler said. “We will set the signal timing to allow the green phase to operate for a certain number of seconds. The issue with that is it is only for the peak, the worst-case scenario. The traffic is not always going to be like that all the time.”
The city has budgeted $2 million for the two phases of the project, with $1.7 million of the funding coming through grants.
The first phase of the project focuses on traffic signals around the city center along South 320th Street and Pacific Highway South and side streets. Phase two continues south along Pacific Highway and includes intersections along south 336th, 348th and 356th streets.
Winkler said it will take about a year to develop a concept of operation and get the requests for proposal from potential vendors.
In addition to the adaptive signal control system, a small traffic management center will be built at City Hall where a traffic engineer can monitor cameras at busy intersections.
“It shows them in real time what the corridor looks like,” Winkler said.
The center could be staffed during heavy traffic times.
“What we are looking at wouldn’t be 24/7,” Winkler said. “We are looking at being able to have someone on that during the peak times.”
The project budget includes funding to hire an additional traffic engineer, Winkler said.
Improving traffic flow could help improve commute times as more cars travel the roads.
“In general, you look at what you can do with your transportation network,” Winkler said. “We don’t have anymore space to build more lanes. We are not going to build more roads. It is more cost effective if you can figure out how to arrange the lanes you have in the best way possible. That is really what adaptive control lends itself to.”
The new system can also help reduce pollution, Winkler said.
“It is a more environmental way of dealing with that,” she said. “If we can keep vehicles from sitting there and idling, they are not polluting the air as much.”