1916 - State begins licensing vehicles by class, registering 49,947 passenger cars and 5,700 trucks. The first metal license plates are issued, with white letters on a blue background. Vehicles are required to have two headlights and one taillight. Upon meeting another vehicle, drivers must keep to the right. 1921 - First state gas tax is set at 1 cent per gallon.
State establishes driver's licenses.
Applicants must furnish signatures of two people certifying that the person is a competent driver and has no physical problems that would impair safe driving. The minimum driving age is 15. The penalty for drunken driving is a three-month license suspension. State Patrol is established. 1922 - The Teapot Dome service station, named for the scandal in the administration of President Warren G. Harding, opens on U.S. Highway 410 in Zillah, Yakima County.