Driver Licensing for Double Trailers - California Residents
12804.9. (b) ..., any applicant for a driver's license shall be required to submit to an examination appropriate to the type of motor vehicle or combination of vehicles the applicant desires a license to drive:
(1) Class A includes the following:
(A) Any combination of vehicles, if any vehicle being towed has a gross vehicle weight rating of more than 10,000 pounds.
(B) Any vehicle towing more than one vehicle.
(C) ...
15278. (a) A driver is required to obtain an endorsement issued by the department to operate any commercial motor vehicle that is any of the following: (1) A double trailer. (2) ...
To apply for a commercial driver license, see the
DMV Commercial Driver License webpage.
Driver Licensing For Double Trailers - Nonresidents
12502. (a) The following persons may operate a motor vehicle in this state without obtaining a driver's license under this code: (1) A nonresident over the age of 18 years having in his or her immediate possession a valid driver's license issued by a foreign jurisdiction of which he or she is a resident, ....
(b) Any person entitled to the exemption contained in subdivision (a), while operating, within this state, a commercial vehicle, as defined in subdivision (b) of Section
15210, shall have in his or her possession a current medical certificate of a type described in subdivision (c) of Section
12804.9, which has been issued within two years of the date of operation of that vehicle.
15210. (b) (1) "Commercial motor vehicle" means any vehicle or combination of vehicles which requires a class A or class B license, or a class C license with an endorsement issued pursuant to paragraph (4) of subdivision (a) of Section
15278.
In summary, nonresidents may tow two trailers with a non-commercial license if their base state allows it. If the vehicle is commercial, the driver would also need a valid medical certificate per 12502 CVC.
For a valid medical certificate, see the
DMV website.
Exceptions - STAA Vehicles
35401.5. (a) A combination of vehicles consisting of a truck tractor and semitrailer, or of a truck tractor, semitrailer, and trailer may exceed the length limits (single-unit: 40' maximum; single-trailer: 65-foot; doubles: 65-foot or 75-foot maximum) on the National Network and Terminal Access routes, provided that:
(1) The length of the semitrailer in exclusive combination with a truck tractor does not exceed 48 feet. The semitrailer is not more than 53 feet in length, with two or more rear axles and a maximum 40' KPRA, or with a single axle and a maximum 38-foot KPRA. (For purposes of this paragraph, a motortruck used in combination with a semitrailer, when that combination of vehicles is engaged solely in the transportation of motor vehicles, camper units, or boats, is considered to be a truck tractor.)
(2) For doubles, neither the semitrailer nor trailer exceeds 28 feet 6 inches.
(These are called "STAA" trucks. For an overview history trucks, see
STAA (PDF) diagram.
(b) Subdivisions (b), (d), and (e) of Section 35402 do not apply to combinations of vehicles operated subject to the exemptions provided by this section.