Except as specifically authorized by statute, an authorization in a statute or regulation to transport the effects of an employee or other individual at Government expense is not an authorization to transport an automobile.

Under regulations prescribed under section 5738 of this title, the privately owned motor vehicle or vehicles of an employee, including a new appointee or a student trainee for whom travel and transportation expenses are authorized under section 5723 of this title, may be transported at Government expense to a new official station of the employee when the agency determines that such transport is advantageous and cost-effective to the Government.

An employee may transport only one motor vehicle under subsection (b) of this section during a 4-year period, except when the head of the agency concerned determines that replacement of the motor vehicle during the period is necessary for reasons beyond the control of the employee and is in the interest of the Government, and authorizes in advance the transportation under subsection (b) of this section of one additional privately owned motor vehicle as a replacement. When an employee has remained in continuous service outside the continental United States during the 4-year period after the date of transportation under subsection (b) of this section of his motor vehicle, the head of the agency concerned may authorize transportation under subsection (b) of this section of a replacement for that motor vehicle.