The U.S. Internal Revenue Service's reimbursement rate for business mileage on a personal car has dropped for the second year in a row and the fifth time in 16 years. Beginning on Jan. 1, the rate will be 53.5 cents, down from 54 cents in 2016 and 57.5 cents in 2015. "Fuel prices played a big role in the slight decrease of the standard reimbursement rate, but factors like rising insurance and maintenance prices offset the rate from dropping even further," said Donna Koppensteiner, senior vice president of Runzheimer, which has calculated the rate for the IRS since 1980.