The companies will find out how many miles the cars have been driven, find the mileage difference and calculate how much more fuel the customer used based on average regional fuel prices and combined city-highway mileage. Customers also would get a 15 percent premium for the inconvenience, and the payments would be made with debit cards, Sprague said. The owner of a car in Florida with a one mpg difference who drove 15,000 miles would get would get a debit card for $88.03 that can be refreshed every year as long as the person owns the car, Sprague said.
If all 900,000 owners get cards for $88.03, it would cost the automakers more than $79 million a year.
