I'm not going to write too much about this because this commentary by CNET News.com Chief Political Correspondant Declan McCullagh does a good job of explaining the issues involved.
In the past, the Federal Highway Administration has given funds to certain states to research and test out pilot pay-per-mile programs, in which a Global Positioning System (GPS) unit is installed in cars, and drivers either pay for mileage or pay more of less for a toll road depending on the time and traffic patterns. This is in order to make up projected losses in gas tax revenue (Oregon Government - PDF) due to newer hybrid and diesel engines raising the gas mileage of cars.
This brings up some obvious rights issues, specifically the fact that there are currently no laws that restrict the uses of these GPS units. I can give benefit of the doubt that if this program was instituted officially these laws may be written, but GPS units have already been used to track suspected criminal's cars, and a New York federal judge ruled that court authorization is not needed. This leads me to believe that if this program is instituted across the board the same thing could be done with any other car if there is any so called 'suspicion of wrongdoing' with no court order or warrant needed.
No rule prohibits that massive database of GPS trails from being subpoenaed by curious divorce attorneys, or handed to insurance companies that might raise rates for someone who spent too much time at a neighborhood bar. No policy bans police from automatically sending out speeding tickets based on what the GPS data say.
