Massachusetts gas tax and vehicle mileage charge

Maybe I shouldn't start out with such a politically charged issue but this relates to both Oregon and Massachusetts residents and our current economic turmoil so may be of interest. Massachusetts has been debating for some time whether to increase tolls (significantly) for the tunnels from East Boston and a few other places and/or to increase the gas tax by 19 cents a gallon.

First, I'd like to say that making the people in East Boston responsible for an enormously disproportionate amount of the burden is simply unjust. I'm sure those tunnels didn't cost anywhere near what the Big Dig cost so why should it cost so much to drive through them? And, we certainly don't want to encourage people to drive the long way around, which would add to traffic congestion and pollution.

The real issue I have though is that 1 cent of the 19 cent gas tax (which doesn't sound like much but is over 5% of the total taxes that will be collected) is going to STUDY the concept of instituting a system to track vehicle miles driven so that another tax can be added based on how many miles you drive your car. This is insane. If you drive more than your neighbor you already pay more for gas and therefore are paying more gas taxes. The system would work by embedding chips in registration stickers on cars that would transmit a signal to various stations along roads, highways, whatever. Why would we spend money building the infrastructure to do this when we have an existing way of collecting revenue from people that is proportionate to the amount of miles they travel. This is technology for the sake of technology.

The only variable between vehicle miles traveled and a straight gasoline tax is from how good your gas mileage is on your car but by charging the gas tax we are already encouraging people to drive more fuel efficient cars. This program will cost a lot of money to collect funds that can already be collected in a much more efficient manner.

My question here for the Oregonians is that part of the argument for implementing the vehicle miles traveled tax is that this is already being done successfully in Oregon--I have never heard of this but maybe this has been done since I've moved away. Is it done in Oregon and if so, what are your thoughts on it?