301-72.2—May we utilize methods of transportation other than common carrier (e.g., POVs, chartered vehicles, etc.)?
Yes, but only when use of common carrier transportation:
(a)
Would interfere with the performance of official business;
(b)
Would impose an undue hardship upon the traveler; or
(c)
When the total cost by common carrier would exceed the cost of the other method of transportation.