Vehicle Lengths | Caltrans (2023)

Summarized here are the California Vehicle Code (CVC)sections related to vehicle lengths. Most of the CVC sections on this web pageare paraphrased for brevity. For the full legal wording, please go to theon-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 thesetopics below: Vehicle Combination, Exceptions - STAA Vehicles

Single Unit Length - Basic Law

35400. (a) "A vehicle may not exceed a length of 40feet." A vehicle is defined in CVC Section 670 as: "...a device by which any person or property may bepropelled, moved, or drawn upon a highway, excepting a device moved exclusivelyby human power or used exclusively upon stationary rails or tracks." Accordingto 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 isexcluded from the measurement of semitrailer length when used between thefirst and second semitrailers of a truck tractor-semitrailer-semitrailercombination. However, if there is no second semitrailer, it shall beincluded in the length measurement of the semitrailer to which it isattached.


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 lengthof 65 feet. (See CaliforniaLegal Trucks (PDF))

(b) (1) A combination of vehicles which consists of a truck tractor, a semitrailer, and a semitrailer or trailer, may notexceed 75 feet, if neither the semitrailers nor the trailer inthe combination of vehicles exceeds 28 feet 6 inches. (See CaliforniaLegal Doubles (PDF))

Number of Vehicles in Combination

21715. (a) No passenger vehicle, or any other motorvehicle under 4,000 pounds, shall tow more than one vehicle,except for a tow dolly. (b) No motor vehicle under 4,000 pounds unladen shalltow 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. Theterm "passenger vehicle" shall include a housecar.

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

410. A "motor truck" or "motortruck" is a motor vehicle designed, used, ormaintained primarily for the transportation of property. (A pick up truck meetsthis 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 tosubmit to an examination appropriate to the type of motor vehicle or combinationof 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 vehicleweight 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 ofthe 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 statewithout obtaining a driver's license under this code: (1) A nonresident over theage of 18 years having in his or her immediate possession a valid driver'slicense issued by a foreign jurisdiction of which he or she is a resident, ....

(b) Any person entitled to the exemption contained insubdivision (a), while operating, within this state, a commercialvehicle, as defined in subdivision (b) of Section 15210, shall have in his or her possession a current medicalcertificate of a type described in subdivision (c) of Section 12804.9, which has been issued within two years of the date of operation ofthat vehicle.

15210. (b) (1) "Commercial motor vehicle" means any vehicle or combinationof vehicles which requires a class A or class B license, or aclass C license with an endorsement issued pursuant to paragraph (4) ofsubdivision (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 combinationwith a truck tractor does not exceed 48 feet. The semitrailer is not more than 53 feet in length, withtwo or more rear axles and a maximum 40' KPRA, or with asingle axle and a maximum 38-foot KPRA. (For purposes of thisparagraph, 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 trucktractor.)

(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 notapply to combinations of vehicles operated subject to the exemptions provided bythis section.

Service Access

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

Terminal Access Applications

(d) The Department of Transportation or local authorities mayestablish a process whereby access to terminals or services may beapplied 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 anengineering analysis. If a written request has not been acted uponwithin 90 days of receipt by the department or the localagency, the access shall be deemed automatically approved. Thereafter, the routeshall be deemed open to all other STAA vehicles. The Department ofTransportation or local authorities may provide signing, mapping, or alisting 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 amotor carrier maintains operating facilities.

(e) Nothing in (c) or (d) authorizes state or localagencies 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 recommendrestricting the maximum kingpin to rear axle (KPRA) lengths oncertain highways, but to not less than 38 feet. By January 1,1989, the Department shall erect advisory signs on statehighways that cannot safely accommodate trailers or semitrailers of the maximumkingpin to rearmost axle distances permitted.

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

Local Length Prohibitions

35401. (d) Any city or county may prohibit acombination 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 lengthof not more than 75 feet, if it is an agriculturalproduct hauler, and complies with a number of requirements.

Tow Trucks

35401. (c) A tow truck is exempt from the65-foot maximum combination limit when operating with an annualtransportation permit, within a 100-mile radius, and in combinationwith 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-steeredsemitrailer, 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 apoint of loading or unloading of household goods, if travel on highways otherthan those specified in subdivision (a) is necessary and incidental to theshipment of the household goods.

Motorsports Events

(g) (1) The Department of Transportation or local authoritiesmay issue a permit authorizing a combination of vehicles consisting of a STAAvehicle 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 insubdivision (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 totransport agricultural biomass may extend to a total combinedlength of 75 feet, under certain circumstances.

Extensions - Length Measurement

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

(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, oron the front of the first trailer, depending on the route used.

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

(e) A truck semitrailer combination, but nota truck tractor and semitrailer combination, may use a sliding fifthwheel, 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 theoverall length of the combination, under certain conditions.

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

Load Lengths


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

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

35407.5. Certain requirement in the previous two sections donot 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 morethan two feet forward of the fenders or cab structure orradiator.

35409. (a) Any motor vehicle used for taking photographs, motion pictures, or television pictures or forteaching 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 asemitrailer is the distance between the rearmost axle of the towing vehicle andthe rearmost axle of the semitrailer.

35411. The load upon any combination of vehicles shall notexceed 75 feet.

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

Island Prohibitions

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

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