49 U.S.C. § 14505
A State or political subdivision thereof may not collect or levy a tax, fee, head charge, or other charge on—
- (1)a passenger traveling in interstate commerce by motor carrier;
- (2)the transportation of a passenger traveling in interstate commerce by motor carrier;
- (3)the sale of passenger transportation in interstate commerce by motor carrier; or
- (4)the gross receipts derived from such transportation.