Oregon was the first state in the country to raise money for road construction by taxing gasoline consumption. The law took effect on February 25, 1919. The tax was $.01 per gallon.
Constructing and paving roads is something all the states were trying to figure out how to pay for, and within ten years every one of them (48 at that time) had followed Oregon’s lead and instituted a similar tax.
For a more thorough history of Oregon’s gasoline and other automobile taxes, visit Joseph Rose’s Hard Drive blog on OregonLive.com: A brief history of Oregon vehicle fees and fuel taxes.