Traffic signs in unincorporated King County

King County's traffic code

King County's traffic code (Chapter 46.04 King County Code) is based on the Washington Model Traffic Ordinance (Washington Administration Code Chapter 308-330) which is in turn based on the Manual on Uniform Traffic Control Devices, or MUTCD, developed by the Federal Highway Administration of the U.S. Department of Transportation.

The MUTCD contains standards for traffic control devices that regulate, warn, and guide road users along the highways and byways in all 50 States. Traffic control devices are important because they optimize traffic performance, promote uniformity nationwide, and help improve safety by reducing the number and severity of traffic crashes.