102-5.20—Who is not covered by this part?
This part does not cover:
(a)
Employees who use a passenger carrier in conjunction with official travel, including temporary duty (TDY) or relocation;
(b)
Employees who are essential for the safe and efficient performance of intelligence, counterintelligence, protective services, or criminal law enforcement duties when designated in writing as such by their agency head; or
(c)
Employees who use a passenger carrier for transportation between places of employment and mass transit facilities (see, e.g., 41 CFR 102-34.210 ).