California Requirements for driving RVs over 40′
It is legal to drive motorhomes over 40 feet but not over 45 feet in length in California. However, there are special requirements and route restrictions for driving motorhomes over 40′ in length.
Note: A vehicle combination, e.g. a motorhome towing a vehicle or trailer, may be up to 65 feet length. If the single-unit motorhome is 40 feet or less in length, the combination is not subject to the route restrictions for the 45′ motorhome.