(a) No passenger shall ride nor shall the operator permit any passenger to ride on the running boards of any motor vehicle while such vehicle is being operated on the streets or highways of this state.
(b) 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.