The requirements of Section 29004 do not apply to a dolly used to support a portion of special construction equipment, as defined in Section 565, which, due to its size or weight is being operated under the authority of a permit issued by the Department of Transportation, if the dolly is secured to the construction equipment, and the construction equipment is secured to the towing vehicle, by chain, cable, or equivalent devices of sufficient strength to control the construction equipment and dolly.