Transit blogs everywhere are going nuts (ref: 1, 2, 3) over the VMT proposal Secretary LaHood proposed. The White House already walked this back and said no such tax was being proposed. The problem for transit followers is that as we go to electric vehicles and reduce gas consumption it affects the national funding for highway repair and transit. Additionally the gas tax is nice but a VMT tax penalizes people for living far away from work and transit groups are anti-sprawl.
A couple of issues jump out for me. First, I am highly sympathetic with the transit crowd but the implementation of this VMT idea is being tied to GPS technology. It is a redux of the electronic voting crowd, look fun new technology is here to needlessly complicate something that works. Maybe we can make it more fragile and less reliable while opening up the possibility of hard to detect fraud. If we try hard we can open up tons of privacy concerns and increase our cost as well.
There already exists a simple mandatory technology that is in every car on the road to track miles driven. The odometer is simple, it is relied on for warranties, for assessing value and already has been made reasonably tamper-proof. Additionally the legislative and social penalties for tampering with the odometer already exist. If we want a VMT, establish various weight classes so that the 300lb EV doesn't pay the same VMT as a 4 ton SUV and base it on yearly odometer readings. Simple, easy to administer and free of troubling privacy concerns. It also requires zero retrofitting.
Secondly, I don't think this is the year for the VMT. There is a lot happening this year, we have health care reform, the second depression to scoop ourselves out of and two wars going on. Wait for 2010 for this kind of action, but remove the unnecessary technology, it is just a waste of time and energy.