The proposal to monitor our miles driven using GPS and to charge user fees based on miles driven is wrong on so many counts that I can't see why it would ever be proposed.
- It greatly increases potential state surveillance in a time when there's already a huge lack of privacy. Oh, sure, these GPS devices only record your whereabouts, but every gas pump in the state can download your worldline - how secure can that be? And you certainly couldn't claim that a warrant would be needed to access the information.
- It punishes light, gas-efficient vehicles by removing consumption from taxation. A per-gallon gas tax already provides good capitalist incentives to avoid gross and inefficient consumption. This would take it away. You Prius drivers? You're screwed.
- It heavily subsidizes heavy vehicles' road use, since they are much more damaging to the infrastructure. That motorcycle you're riding could drive over the roads and bridges of Massachusetts without ever causing any damage. Even wear would take many, many years. Appropriate taxes and user fees on semis - to cover their costs - would make rail more attractive economically.
Update (2/20): President Obama is not going ahead with this. Joy!