Cal. Code Regs. tit. 8, § 7018 – Trackless Mine Haulage--Equipment and Practices.

(a) Every trackless haulage vehicle shall be provided with adequate power to carry its load safely up any grade over which it operates.
(b) A safe seat shall be provided for the operator of the vehicle. The seat shall be constructed so it will prevent the operator from slipping over the back or sides of the seat.
(c) Haulage vehicles shall be equipped with headlights and at least one taillight in good condition.
Such vehicles shall be equipped with backup lights which function automatically when the vehicle is put in reverse gear.