On July 17, GMAC Insurance and OnStar officially launched their new Low-Mileage Discount Program. Under the plan, OnStar and GMAC customers can have their premiums cut anywhere from 13 to 54 percent if they each drive less than 15,000 miles annually, reports the Detroit Free Press.OnStar subscribers automatically receive monthly email reports with maintenance information on four of the car’s key operating systems. If they decide to join the Low-Mileage program, OnStar forwards the monthly odometer readings to GMAC, which uses the mileage reports to calculate insurance discounts.GMAC President Gary Kusumi says that even though mileage is the most important factor in insurance risk, this is the first time insurance providers have been able to accurately tie the two together. In the past, insurance companies had little more than the customer’s word to rely on when they reported their mileage. The partnership with OnStar resolves that problem.Although OnStar has assured consumers they will forward only the mileage data to GMAC, they have kept the program optional to alleviate any privacy concerns, according to the report.GMAC currently offers the Low-Mileage Discount in 34 states, and they plan to add more next year.