(a) The driver of any motor vehicle when traveling upon a down grade shall not coast with the gears of such vehicle in neutral.
(b) The driver of a commercial motor vehicle when traveling upon a down grade shall not coast with the clutch disengaged.
(c) Any person violating the provisions of this section is guilty of a misdemeanor and, upon conviction thereof, shall be fined not more than $100; upon a second conviction within one year thereafter, shall be fined not more than $200; and upon a third or subsequent conviction, shall be fined not more than $500.