Well now this is interesting:

Engineers at the University of Minnesota (UMinn) have devised a plug-in device for measuring vehicle-miles traveled and logging it for road use charges (RUC) that they say could be deployed near-term. The system makes use of an electronic processor and memory that can be plugged into an existing vehicle data bus via a Data Link Connector plug, and which uses cellphone data links. The data link connector at the heart of the UMinn proposal is already installed in all vehicles manufactured in North America since 1996. Its primary purpose is for engine diagnostics at repair garages and emission control monitoring…

With most vehicles already equipped with the needed data link connector plug, and making use of the existing cellphone infrastructure UMinn RUC devices could be in use nationwide within a couple of years.

The basic UMinn plug-in RUC device is designed primarily to measure distance traveled since the highest priority is seen by the authors as being a charge that replaces the gasoline/diesel fuel tax as the primary funding for roads…

For the VMT uploads to the billing office the UMinn RUC proposal uses SMS/text messaging, now generally available in the US via cellphone networks. It is not dependent on gasoline stations.

Something like this would be advantageous in that it wouldn’t up the Big Brother quotient, since most drivers are already being tracked by cell towers. And the engineers suggest that this system would be far more effective in dense urban areas than GPS tracking anyway. There could be some potentially interesting user feedback mechanisms, as well, with drivers informed by text how much they’ve been driving and how much they’ve paid for those miles.

Legislators will most likely have two years to mull over the funding question before a reauthorization is actually passed. That would seem to be plenty of time to incorporate plans for a congestion tolling or VMT tax system.