Typically, commercial air is the preferred mode of transportation for TDY. However, if the trip is 800 miles round trip or less, then the traveler is authorized to drive a POV and the traveler is not required to complete a cost comparison. See the JTR, par. 020210.
For TDY travel, an authorizing official may authorize a Service member or civilian employee to use non-motorized transportation, such as bicycling, for official TDY travel. However, the traveler does not receive a mileage allowance for official travel by non-motorized transportation. An authorizing official may authorize reimbursement for non-motorized transportation-related expenses only if it is in the Government’s interest. Reimbursement of transportation-related expenses must not exceed the cost of the transportation mode that the authorizing official determines is most advantageous to the Government.
One kilometer equals 0.62 miles. To convert kilometers to miles, multiply the number of kilometers by 0.62. The answer is the equivalent number of miles.
For example, to convert 84 kilometers to miles, multiply 84 by 0.62. The answer is 52 miles.
One nautical mile equals 1.15077945 miles. To convert nautical miles, multiply the nautical distance by 1.15077945. The answer is the equivalent number of miles.
For example, to convert 84 nautical miles to miles, multiply 84 by 1.15077945. The answer is 96 miles.