Vehicle Lengths

Summarized here are the California Vehicle Code (CVC) sections related to vehicle lengths. Most of the CVC sections on this web page are paraphrased for brevity. For the full legal wording, please go to the on-line CVC Length Section 35400.

For a graphic illustration of the length dimensions of California Legal (black truck) and STAA (green truck) vehicles with both single trailers and doubles, view the Truck Map Legend (PDF).

For a legal explanation of the green STAA vehicles, see these topics below: Vehicle Combination, Exceptions - STAA Vehicles

Single Unit Length - Basic Law

35400. (a) "A vehicle may not exceed a length of 40 feet." A vehicle is defined in CVC Section 670 as: "...a device by which any person or property may be propelled, moved, or drawn upon a highway, excepting a device moved exclusively by human power or used exclusively upon stationary rails or tracks." According to this definition, a vehicle includes a trailer being towed. (See Single Vehicle (PDF) diagram)

Exceptions to Maximum Single-Unit Length

The following are not included in the 40' maximum length:
35400. (b)

  1. Auxiliary parts. (See Auxiliary Parts in a Combination (PDF) diagram)
  2. fender and mudguard parts if required. (See Single Vehicle (PDF) diagram)
  3. (A) An articulated bus or articulated trolley coach not exceeding 60 feet. (B) An articulated bus or articulated trolley coach with a 36-inch folding device attached to the front for transporting bicycles.
  4. A semitrailer while being towed by a motortruck or truck tractor, if the kingpin-to-rearmost-axle (KPRA) distance of the semitrailer does not exceed 40 feet for semitrailers having two or more axles, or 38 feet for semitrailers having one axle. (See One Axle Semitrailer (PDF) and Two or More Axle Semitrailer (PDF) diagrams)
  5. A 1-foot front or rear safety bumper on a bus or house car.
  6. A 10-inch crossing arm on a school bus.
  7. An 18-inch wheelchair lift on a bus.
  8. A 10-foot bike rack on a bus, if the total length doesn't exceed 50 feet.
  9. A 36-inch bike rack on a 40' transit bus.
  10. (A) A 36-inch bike rack on a 45'bus on approved routes.
  11. (A) A 45' house car (or "motorhome") on approved routes.

Exceptions - Cotton Module Mover

35400.5. A 48-foot motortruck used as a cotton module mover.

Exceptions - B-Train Assembly

35401. (b) (2) A B-train assembly is excluded from the measurement of semitrailer length when used between the first and second semitrailers of a truck tractor-semitrailer-semitrailer combination. However, if there is no second semitrailer, it shall be included in the length measurement of the semitrailer to which it is attached.


A forklift that is lifted off the ground and is being transported on the back of a truck is not included in the length measurement, as it is considered a load.

Vehicle Combinations - Basic Law

35401. (a) No vehicle combinations may exceed a total length of 65 feet. (See California Legal Trucks (PDF))

(b) (1) A combination of vehicles which consists of a truck tractor, a semitrailer, and a semitrailer or trailer, may not exceed 75 feet, if neither the semitrailers nor the trailer in the combination of vehicles exceeds 28 feet 6 inches. (See California Legal Doubles (PDF))

Number of Vehicles in Combination

21715. (a) No passenger vehicle, or any other motor vehicle under 4,000 pounds, shall tow more than one vehicle, except for a tow dolly. (b) No motor vehicle under 4,000 pounds unladen shall tow any vehicle weighing 6,000 pounds or more gross.

465. A "passenger vehicle" is any motor vehicle, other than a motortruck, truck tractor, or a bus, as defined in Section 233, and used or maintained for the transportation of persons. The term "passenger vehicle" shall include a housecar.

362. A "house car" is a motor vehicle originally designed, or permanently altered, and equipped for human habitation, or to which a camper has been permanently attached. ...

410. A "motor truck" or "motortruck" is a motor vehicle designed, used, or maintained primarily for the transportation of property. (A pick up truck meets this definition.)

471. A "pickup truck" is a motor truck with a manufacturer's gross vehicle weight rating of less than 11,500 pounds, an unladen weight of less than 8,001 pounds, and which is equipped with an open box-type bed not exceeding 9 feet in length. "Pickup truck" does not include a motor vehicle otherwise meeting the above definition, that is equipped with a bed-mounted storage compartment unit commonly called a "utility body."

If a "pickup truck" has a manufacturers gross vehicle weight rating (GVWR) of 11,500 pounds or more, it would not meet the definition of “pickup truck” in Section 471 and would, therefore, be considered a motor truck (see Section 410 above).  If the power unit is classified as a motor truck, and the vehicle combination (including any load carried) exceeds 10,000 pounds, then the vehicle must be registered with the Department of Motor Vehicles as a commercial vehicle with a declared operating weight.  If the power unit has a GVWR under 11,500 pounds, then it would not be required to declare an operating weight. 

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.

Service Access

(c) STAA vehicles may also use highways which provide reasonable access to terminals and facilities for purposes limited to fuel, food, lodging, and repair when that access is safe and when the facility is within one road mile of identified exits.

Terminal Access Applications

(d) The Department of Transportation or local authorities may establish a process whereby access to terminals or services may be applied for upon a route not previously established as an access route. The denial of a request shall be only on the basis of safety and an engineering analysis. If a written request has not been acted upon within 90 days of receipt by the department or the local agency, the access shall be deemed automatically approved. Thereafter, the route shall be deemed open to all other STAA vehicles. The Department of Transportation or local authorities may provide signing, mapping, or a listing of highways to indicate terminal access routes. "Terminal" means either of the following: (1) A facility where freight originates, terminates, or is handled in the transportation process. (2) A facility where a motor carrier maintains operating facilities.

(e) Nothing in (c) or (d) authorizes state or local agencies to require permits or to charge fees for the purpose of attaining access.

KPRA Limits

35401. (e) Any city or county may restrict the kingpin to rearmost axle distance to 38 feet, but not less, on those highways under its jurisdiction.

35401. (f) The Department of Transportation may recommend restricting the maximum kingpin to rear axle (KPRA) lengths on certain highways, but to not less than 38 feet. By January 1, 1989, the Department shall erect advisory signs on state highways that cannot safely accommodate trailers or semitrailers of the maximum kingpin to rearmost axle distances permitted.

35401.1. A combination of vehicles with a KPRA of 38 to 40 feet may be operated on local highways only where it is deemed to be safe by the owner or operator of the vehicle.

Local Length Prohibitions

35401. (d) Any city or county may prohibit a combination of vehicles of a total length in excess of 60 feet upon highways under its jurisdiction.


Rear Fairings

35405. A rear fairing installed on the back of a semitrailer for aerodynamic purposes, up to five feet in length, is not included in the length measurements of the semitrailer or the vehicle combination. (See CVC Section 35405.)

Agricultural Product Haulers

35401. (b) (3) A vehicle combination may have a total length of not more than 75 feet, if it is an agricultural product hauler, and complies with a number of requirements.

Tow Trucks

35401. (c) A tow truck is exempt from the 65-foot maximum combination limit when operating with an annual transportation permit, within a 100-mile radius, and in combination with a disabled and/or abandoned vehicle.

Auto, Boat, & Camper Transporters

35401.3. (a) A combination of vehicles designed and used to transport motor vehicles, camper units, or boats, which consists of a motortruck and stinger-steered semitrailer, shall be allowed a length of up to 70 feet, or 75 feet, depending on certain conditions.

Household Goods Movers

(f) The limitations of access do not apply to licensed carriers of household goods when directly enroute to or from a point of loading or unloading of household goods, if travel on highways other than those specified in subdivision (a) is necessary and incidental to the shipment of the household goods.

Motorsports Events

(g) (1) The Department of Transportation or local authorities may issue a permit authorizing a combination of vehicles consisting of a STAA vehicle with a KPRA of not more than 46 feet on trailers used in connection with motorsports.)

Livestock Haulers

35401.7.(a) The limitations of access specified in subdivision (d) of Section 35401.5 do not apply to licensed carriers of livestock on certain routes and under certain circumstances.

Agricultural Biomass Haulers

35401.8. (a) A combination of vehicles designed and used to transport agricultural biomass may extend to a total combined length of 75 feet, under certain circumstances.

Extensions - Length Measurement

35402. (a) Any extension used to increase the carrying capacity of a vehicle shall be included in measuring the length of a vehicle. However, a drawbar shall be included in measuring the overall length of a combination of vehicles, but not the length of a vehicle.

(b) Extensions up to 18 inches in length on auto haulers (car carriers) shall not be included when loaded.

(c) An extension of up to 18 inches on the last trailer shall not be included, or on the front of the first trailer, depending on the route used.

(d) Any extension not used to carry a load and not exceeding three feet on the rear of a vehicle for pushing the vehicle or a combination that is for to transporting earth, sand, gravel shall be included in the length of the vehicle but not the overall length of the combination of vehicles.

(e) A truck semitrailer combination, but not a truck tractor and semitrailer combination, may use a sliding fifth wheel, or a truck tractor, semitrailer, trailer, and a truck-trailer combination may use a sliding drawbar, to extend the combination by not more than 2 feet 6 inches while traveling 35 miles per hour or less on any highway, freeway onramps and offramps, and freeway connectors, but not a freeway. The sliding fifth wheel or drawbar shall not be included in the overall length of the combination, under certain conditions.

35403. Safety devices which are required to be mounted upon a vehicle may extend beyond the permissible vehicle length up to 10 inches.

Load Lengths


35406. The load upon any vehicle or the front vehicle of a combination of vehicles, shall not extend more than three feet beyond the foremost part of the front tires of the vehicle or the front bumper of the vehicle, or four feet, if the load is composed solely of vehicles.

35407. Section 35406 does not apply to booms or masts of shovels, cranes or water well drilling and servicing equipment carried upon a motor vehicle in certain conditions

35407.5. Certain requirement in the previous two sections do not apply to the booms or masts of a self-propelled heel-boom log loader first sold in this state prior to January 1, 1988, in certain conditions.

35408. A front bumper may not project more than two feet forward of the fenders or cab structure or radiator.

35409. (a) Any motor vehicle used for taking photographs, motion pictures, or television pictures or for teaching safe driving may be equipped with a device extending forward five feet.)


35410. The load shall not extend to the rear more than two-thirds of the wheelbase. The wheelbase of a semitrailer is the distance between the rearmost axle of the towing vehicle and the rearmost axle of the semitrailer.

35411. The load upon any combination of vehicles shall not exceed 75 feet.

35414. (a) Poles, timbers, pipes, integral structural materials, or single unit component parts may not exceed 80 feet when transported upon certain equipment. (b) A public utility company or local public agency may transport up to three poles not exceeding 80 feet on a pole or pipe dolly.

Island Prohibitions

35404. Any county having a population in excess of 4,000,000 and having within its limits a natural island with an area in excess of 20,000 acres may prohibit the use of any highway or lane (1) by any vehicle exceeding an overall length of 170 inches and an overall width of 65 inches, or (2) by any such vehicle and all vehicles driven by internal combustion engines.