Do electric cars make the gas tax obsolete?

I am concerned not to have heard or read any discussion of the impact the introduction of electric cars will have on revenues raised from gasoline taxes.

How will we be able to meet our commitment to first-class roads whose upkeep depends on revenues raised from taxes on gasoline? Within 10 years there may be a sizable number of electric cars on the road, and they won't be paying taxes on gasoline.

Are there any plans to address to this loss of revenue? Electrically powered cars will be using our roads, but they won't be paying for the privilege.

Alvin Bober, Owings Mills