Someone is Overthinking the Problem

This article at AutoBlogGreen (original WSJ article) describes the pilot program that Oregon is conducting to tax drivers per mile instead of per gallon. This pilot program requires installing a GPS system on participating vehicles that tracks the number of miles driven. When the driver refuels, the GPS unit uploads the miles traveled and resets. The specially equipped gas pump calculates the tax based on the mileage instead of the gallons pumped.

There have been a few criticisms of this system. The first is that fuel efficient vehicles are taxed at a higher rate per gallon then gas guzzlers. The second is that while Oregon says that they do not track where the owners have been, and I believe them, they may have the ability to determine where the owners are at any given time, a clear privacy issue. In addition to the two issues above, my issues are that heavier vehicles cause greater wear to the road and therefore the tax per gallon is fairer. Second, installing these units in all cars and equipping all gas pumps just seams so unnecessary and expensive. If the end goal is truly to increase revenues for road projects, why not just raise the current gas tax?