Washington State

Office of the Attorney General

Attorney General

Bob Ferguson

AGO 1967 NO. 12 >

Since state law prohibits the erection or maintenance, without approval of the state highway commission, of any traffic control device on a city street which has been designated as a part of the state highway system, a city of the third class, operating under the commission form of government, may not construct "speed control bumps" (consisting of raised portions of asphaltic paving) on any of its streets which have been so designated without prior approval from the highway commission; in the case of city streets which are not a part of the state highway system, a third class city operating under the commission form of government may install such "speed control bumps" if, under all circumstances, they constitute a reasonable means of controlling the speed of traffic and do not pose an unreasonable danger or hazard to such traffic.