N.Y. Comp. Codes R. & Regs. tit. 20 § 481.12
Mileage within this State shall be computed on the basis of the actual mileage traveled by each motor vehicle. For the records required to be maintained by carriers, see Part 483 of this Subchapter. Such mileage shall be computed by the most accurate measure of the actual miles traveled by each motor vehicle, including but not limited to measurement based on odometer readings, fuel consumption records, map mileage from point of origin to point of destination plus any off-route mileage and local mileage not ascertainable from the map, tariff schedules and mileage used for billing purposes plus any additional mileage not includible in billing, tachograph readings, hubometer readings or any other devices or means for accurately measuring actual mileage. The use of any of the foregoing methods to determine the mileage is not intended to produce a mileage that is less than the actual mileage traveled. The computed mileage shall be subject to audit by the State Tax Commission, using the most accurate method for determining actual mileage.
N.Y. Comp. Codes R. & Regs. Tit. 20 § 481.12