California Vehicle Code
Sec. § 385.2


A “logging dolly” is a vehicle designed for carrying logs, having one or more axles that, if there are more than one, are not more than 54 inches apart, and used in connection with a motor truck solely for the purpose of transporting logs and securely connected with the towing vehicle both by a reach and by the load.
Source
Last accessed
Jun. 6, 2016