@Carl
See https://www.irs.gov/taxtopics/tc510
Standard Mileage Rate
To use the standard mileage rate for a car you own, you must choose to use it in the first year the car is available for use in your business. Then, in later years, you can choose to use the standard mileage rate or actual expenses.
[Also note that if you choose the standard mileage rate in the first year, you can continue to use it even if the depreciation component results in the accumulated depreciation going below the basis of the vehicle]
