mileage

Oregon is moving ahead with a controversial plan to tax motorists based on the number of miles they drive as opposed to the amount of fuel they consume, raising myriad concerns about cost and privacy.

The program, springing out of a recently signed bill, is expected to launch in 2015 on a volunteer basis. But it’s charting relatively new territory, and other states aching for additional tax revenue are sure to be watching closely to see whether to imitate the model.

The problem for lawmakers is that the existing per-gallon gas tax has hit a point of diminishing returns, as Americans drive less and vehicles become more fuel efficient. The federal Highway Trust Fund, which gives money to states for highway construction and repairs, for example, has needed a congressional bailout four times since 2009, in part the result of no federal gas tax increase in the past 20 years.