5 CFR § 551.422 - Time spent traveling.
(a) Time spent traveling shall be considered hours of work if:
(1) An employee is required to travel during regular working hours;
(2) An employee is required to drive a vehicle or perform other work while traveling;
(3) An employee is required to travel as a passenger on a one-day assignment away from the official duty station; or
(4) An employee is required to travel as a passenger on an overnight assignment away from the official duty station during hours on nonworkdays that correspond to the employee's regular working hours.
(b) An employee who travels from home before the regular workday begins and returns home at the end of the workday is engaged in normal “home to work” travel; such travel is not hours of work. When an employee travels directly from home to a temporary duty location outside the limits of his or her official duty station, the time the employee would have spent in normal home to work travel shall be deducted from hours of work as specified in paragraphs (a)(2) and (a)(3) of this section.
(c) An employee who is offered one mode of transportation, and who is permitted to use an alternative mode of transportation, or an employee who travels at a time other than that selected by the agency, shall be credited with the lesser of:
(1) The actual travel time which is hours of work under this section; or
(2) The estimated travel time which would have been considered hours of work under this section had the employee used the mode of transportation offered by the agency, or traveled at the time selected by the agency.
(d) Except as provided in paragraph (b) of this section, an agency may prescribe a mileage radius of not greater than 50 miles to determine whether an employee's travel is within or outside the limits of the employee's official duty station for determining entitlement to overtime pay for travel under this part. However, an agency's definition of an employee's official duty station for determining overtime pay for travel may not be smaller than the definition of “official station and post of duty” under the Federal Travel Regulation issued by the General Services Administration (41 CFR 300-3.1).