Ill. Admin. Code tit. 80, § 3000.610 – Expenses Related to Transportation

a) Reimbursement for the cost of automobile parking fees and tolls shall be allowed. Parking fees at a terminal or other parking area while the traveler is away from headquarters shall be allowed.
b) When the use of a common carrier is a reasonable alternative, the mileage payment shall not exceed the cost of its use. A reasonable alternative exists when the cost of travel, taking into account both transportation, time and meal expenses would be less if a common carrier were used.
c) Where the nature and location of work at a temporary duty station are such that suitable meals cannot be procured there, the expenses of daily travel required to procure meals at the nearest available place shall be considered necessary transportation. A statement of the necessity for such daily travel shall accompany or be noted on the travel voucher.