The technology for charging drivers for their use of the roads based on the miles they actually drive keeps getting closer to maturity. This article describes some pioneering research at Oregon State University.

Hybrid engines may before long create a crisis for state highway maintenance funding. By-the-mile fees may then replace by-the-gallon taxes. Along the way, the fees could be fine tuned to reflect things like vehicle size (and the danger it poses to other vehicles and pedestrians), emissions, and rush-hour driving.