41 CFR § 302-7.102
How is the mileage distance determined under the commuted rate method?
June 9, 2020
To determine the distance from the authorized origin to the authorized destination, you may use the tariffs filed with GSA travel management centers or any other mileage guide authorized by your agency.
Note to §§302-7.100 and 302-7.102: Any substantial deviation from the distances shown in the authorized mileage guides must be explained on the travel claim.
[FTR Amdt. 98, 66 FR 58196, Nov. 20, 2001, as amended by FTR Amdt. 2013-03, 78 FR 75484, Dec. 12, 2013]