The IRS issued a New Year's Eve news release announcing that the standard mileage rate for business miles will drop to 57.5 cents per mile as of 1/1/20, down a half cent from the 2019 rate of 58.0 cents per mile. As a result, the California workers' compensation medical mileage rate will also drop to 57.5 cents per mile for travel on or after January 1, 2020.