Veh. Code, § 29004

(a) (1) Except as required under paragraph (2), a towed vehicle shall be coupled to the towing vehicle by means of a safety chain, cable, or equivalent device in addition to the regular drawbar, tongue, or other connection.

(2) A vehicle towed by a tow truck shall be coupled to the tow truck by means of at least two safety chains in addition to the primary restraining system. The safety chains shall be securely affixed to the truck frame, bed, or towing equipment, independent of the towing sling, wheel lift, or under-reach towing equipment.

(3) A vehicle transported as a load on a trailer, using vehicles other than those described in Section 34500, shall be secured by at least four tiedown chains, straps, or an equivalent device, independent of the winch or loading cable.

(b) All safety connections and attachments shall be of sufficient strength to control the towed vehicle in the event of failure of the regular hitch, coupling device, drawbar, tongue, or other connection. All safety connections and attachments also shall have a positive means of ensuring that the safety connection or attachment does not become dislodged while in transit.

(c) No more slack may be left in a safety chain, cable, or equivalent device than is necessary to permit proper turning. When a drawbar is used as the towing connection, the safety chain, cable, or equivalent device shall be connected to the towed and towing vehicle and to the drawbar so as to prevent the drawbar from dropping to the ground if the drawbar fails.

(d) Subdivision (a) does not apply to a semitrailer having a connecting device composed of a fifth wheel and kingpin assembly, and does not apply to a towed motor vehicle when steered by a person who holds a license for the type of vehicle being towed.

(e) For purposes of this section, a “tow truck” includes both of the following:

(1) A repossessor’s tow vehicle, as defined in subdivision (b) of Section 615.

(2) An automobile dismantler’s tow vehicle, as defined in subdivision (c) of Section 615.

(f) A vehicle towed by a repossessor’s tow vehicle, as defined in subdivision (b) of Section 615, is exempt from the multisafety chain requirement of paragraph (2) of subdivision (a) so long as the vehicle is not towed more than one mile on a public highway and is secured by one safety chain.