From staff reports:

Federal Way public works crews installed a flashing yellow turn signal Tuesday at Pacific Highway South and South 316th Street.

The flashing yellow arrows allow drivers to turn during gaps in oncoming traffic instead of waiting for a green arrow signal. The turn signals from Pacific Highway will only operate as flashing yellow signals during low traffic volume periods of the day and week. Otherwise, the turn signals will operate as standard solid green arrows, according to the city.

The new flashing yellow signals are intended to provide more turning time for Metro buses that turn onto South 316th Street en route to the Federal Way Transit Center, according to the city. The new signals are expected to improve traffic flow and reduce waiting times for turns.

The city reports that the signal upgrade at this intersection, which sees about 35,000 vehicles daily, will cost about $15,000.

The city installed its first flashing yellow signal in 2006. Flashing yellow signals can be found at 12 intersections throughout Federal Way. Collisions at those intersections have decreased by 23 percent, while the severity rates of collisions at those intersections have decreased 34 percent, according to the city.