Metering car usage to save the environment?

Click on this link to read a NY Times story about a Dutch pilot project metering car actual usage as a basis for taxation. Rather than charging citizens a tax when buying petrol for their cars, the meter would track, in a very detailed way, how the person actually uses their car (and how much). Gas hogs who waste gas would be taxed at a higher rate. Participants in the project were able to see the tax meter rising and immediately changed their driving habits. Critics worry about privacy concerns, since the meter uses GPS technology to track drivers' travel. GPS units have already played a role in a number of criminal cases and trials, providing valuable evidence of the accused's activities. If this new meter technology caused people to drive less and more efficiently, would it we worth the intrusion to save our climate and roads?