Traffic Control

Report a malfunctioning traffic signal or flashing beacon:

Email: luttraffic@co.washington.or.us

Phone: 503-846-7950

Washington County maintains and operates about 350 traffic signals and 200 flashing beacons. The County’s Traffic Engineering section ensures that vehicle, bicycle and pedestrian safety is improved whenever traffic signals are installed.

Traffic signal and all-way stop selection

Washington County installs traffic signals and all-way stops only after a traffic study determines that these controls will improve traffic flow and safety, and that conditions are met. These conditions, called warrants, can include traffic volumes, pedestrian traffic, school crossings, grades, crash history and more. Traffic engineers use standard traffic signal and all-way stop warrants, developed by the Federal Highway Administration (FHWA), to conduct these analyses.

Design and installation cost of a traffic signal is $500,000-1.5 million, depending on the complexity of the intersection. Electricity costs add an additional $600-1200 annually. Traffic signal projects are usually funded either through major road construction projects or through private development. 

Traffic signal advantages:

  • Creates orderly movement of traffic
  • Increases capacity of the intersection
  • Reduces frequency and severity of some of crashes, especially right-angle collisions
  • Creates protected crossing opportunities for bicyclists and pedestrians

Traffic signal disadvantages:

  • Does not prevent all types crashes
  • Could create a false sense of security, particularly for pedestrians
  • Could increase rear-end collisions
  • Could increase cut-through traffic in nearby neighborhood roads
  • Can create unnecessary delays at certain times
  • Can increases air pollution from idling vehicles
  • Can lead to red-light running if travelers don’t feel it’s necessary


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