As I’ve already gotten a lot of feedback this morning from the earlier post on gas taxes, and most of it centers on two issues, let me quickly discuss them.

First, many argue that there is no need to wait for GPS technology to charge drivers according to how much they drive rather than how much gas they buy. Yes, the odometer captures that information, and pretty much everyone gets the odometer checked annually as part of state vehicular registration and emissions programs. But there are two problems. Number 1, unless you want to mandate lots of additional visits to auto shops and emissions testers — and don’t give the relevant lobbies any ideas for new initiatives to push in state legislatures — the odometer would only allow for annual highway-use charges. People are used to paying for highways in dribs and drabs, and wouldn’t like the lump sum one bit (though that would be a nice way to confront them with the real cost of government, as property taxes do for those past the escrow phase of their financial lives). There would probably be a lot of evasion and financing problems. Monthly billing is probably better. More importantly, a key attraction of true usage pricing is that the prices could be adjusted for time of day and highways used. Peak pricing is impossible with an odometer-based system.

The second major objection is that using GPS technology to price road usage is a huge invitation to Big Brother to monitor everyone’s driving habits. I am nervous about the privacy implications, too, though I will point out that as I understand it, carrying a cellphone around gets you pretty far along to that troubling prospect, if Big Brother is so inclined. Still, if the high-tech solution is problematic on privacy grounds, I’d be open to some other solution to the problem of transportation finance, which is very real and inherent in any system based on taxing gas consumption.