The optional standard mileage rates for business use of a vehicle will decrease slightly in 2020 after increasing significantly in 2019, the IRS announced on Tuesday (Notice 2020-05). For business use of a car, van, pickup truck, or panel truck, the rate for 2020 will be 57.5 cents per mile in 2020, down from 58 cents per mile last year. The standard mileage rate also can be used as the maximum amount an employer can reimburse an employee for operating an automobile for business purposes without substantiating the actual expense incurred.