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Truck Size & Routes
STAA: The federal Surface Transportation Assistance Act of 1982.
KPRA: Kingpin-to-rear-axle distance.
Double: A truck tractor that tows a semitrailer and trailer.
STAA Truck: A truck tractor-semitrailer (or double) that conforms to the requirements of the STAA, as described in the table below.
California Legal Truck: A truck tractor-semitrailer (or double) that can travel on virtually any route in California, as described in the table below.
National Network (NN): Primarily the interstates, also called the National System of Interstate and Defense Highways.
Terminal Access (TA) Routes: State or local routes that have been granted access to STAA trucks.
Service Access Routes: Roads that allow STAA truck access for fuel, food, lodging, and repair within one road mile of a signed exit from the National Network.
STAA Network: The routes that allow STAA trucks, which include the National Network (NN), Terminal Access (TA) routes and Service Access routes.
CVC: California Vehicle Code.
Height: Maximum 14 feet from the pavement. (See CVC Section 35250.)
Width: Maximum 102 inches, with certain exceptions. (See CVC Sections 35100-35111.)
Length: Single vehicle -- maximum 40 feet, with certain exceptions. Vehicle combination -- maximum 65 feet. STAA trucks and certain doubles may be longer than 65 feet as follows:
|STAA Truck with Single Trailer:||STAA Truck with Double Trailer:|
Semi-trailer = 48 feet maximum
| Semi-trailer = 28 feet 6 inches maximum
Trailer = 28 feet 6 inches maximum
KPRA = no limit
Combination length = no limit
|California Legal Truck with Single Trailer:||California Legal Truck with Double Trailer:|
Semi-trailer = no limit
|Semi-trailer = 28 feet 6 inches max
Trailer = 28 feet 6 inches max
KPRA = no limit
Combination length = 75 feet max
Either trailer or semi-trailer = 28 feet, 6 inches max; the other trailer has no limit
KPRA = no limit
Combination length = 65 feet max
For an illustration of length dimensions of California Legal (black truck) and STAA (green truck) vehicles, see this web page: "Truck Lengths & Routes -- Quick Guide" at: http://www.dot.ca.gov/hq/traffops/engineering/trucks/truck-length-routes.htm#step-2. (See also the CVC "Length" Section 35401.5.)
STAA TRUCK ROUTES
STAA trucks are limited to the National Network, Terminal Access routes, and Service Access routes (STAA Network), as described below:
National Network (Federal) -- Green Routes: The National Network (NN) are federal highways primarily comprised of the National System of Interstate and Defense Highways, for example I-10, I-5, and I-80. The NN routes are not signed for STAA trucks access. NN routes are illustrated as green routes on the State Truck Route Map.
Terminal Access (State, Local) -- Blue Routes: Terminal Access (TA) routes are portions of State routes or local roads that can accommodate STAA trucks. The State highway TA routes are illustrated as blue routes on the State Truck Route Map. Local TA routes are not illustrated on the State Truck Network Map, but local TA maps are linked from this web page as they become available: Local Truck Maps. A TA symbol sign is posted at decision points as trailblazers to other TA routes, such as in advance of the ramp or intersection, along both State and local TA routes. This sign (#G66-56) is illustrated below:
Service Access (Local): STAA trucks may exit the National Network to access fuel, food, lodging, and repair at facilities that are within one road mile of a signed exit from the National Network. Service Access routes are primarily local roads and are not indicated on the State Truck Network Map. The Service Access symbol sign is posted prior to approved exits on the NN. STAA trucks may exit for services ONLY where indicated by signage. This sign (#G66-55) is illustrated below:
(See CVC "Length" Section 35401.5.)
CALIFORNIA LEGAL TRUCK ROUTES
California Legal trucks may travel on the STAA network and also on the routes listed below:
California Legal (State and Local) -- Black Routes: California Legal trucks can use all State highways in California except those with special restrictions such as for weight or length. (See the section "Special Truck Restrictions" below.) Ca Legal routes are illustrated as black and yellow routes on the State Truck Route Map. (The yellow routes are advisory routes and are described below.) California Legal trucks may also use local "truck routes" as approved and signed by the local government. There is no signage for California Legal black routes.
California Legal (State) -- Yellow Routes: Some California Legal routes are called "advisory routes." Ca Legal Advisory routes are illustrated as yellow routes on the State Truck Route Map. These routes allow California Legal trucks, which are allowed a maximum KPRA length of 40 feet; however, truckers are advised not to use advisory routes unless their KPRA is less than 40 feet. The advised length is posted on the sign, and could be 30, 32, 34, 36, or 38 feet. The most common KPRA advisory is 30 feet. The "Advisory" route sign (SW48(CA)) is illustrated below:
The advisory system was created because Caltrans is prohibited from restricting the KPRA on these routes. A truck with a KPRA longer than that posted may not be able to stay in its lane. Although California Legal trucks may legally travel on advisory routes, the driver is still legally responsible for unsafe offtracking, such as crossing the centerline or driving on shoulders, curbs and sidewalks.
(See CVC "Length" Section 35401.5.)
SPECIAL TRUCK RESTRICTIONS
Some routes have special restrictions, such as for length, gross weight, number of axles, or hauling of flammable materials or explosives. See the red routes on the State Truck Route Map, and the list of special restrictions on the web page: Special Route Restrictions.
MUTCD: For more information on signing truck routes, see the 2012 California Manual on Uniform Traffic Control Devices (CA MUTCD):
- Terminal and Service Access Signs (#G66-56 and #G66-55) on Pages 566-568 at: http://www.dot.ca.gov/hq/traffops/engineering/mutcd/pdf/camutcd2012/Part2GN.pdf
- Advisory Sign (SW48(CA)) on Page 268: http://www.dot.ca.gov/hq/traffops/engineering/mutcd/pdf/camutcd2012/Part2CF.pdf
TERMINAL ACCESS CHANGE REQUEST
State Routes: Caltrans designated all State routes in the 1980's using engineering analyses. Since then, district engineers have continued to upgrade State highways to STAA where possible, due to improvement projects that enhance the geometrics on curves, ramps, and intersections. However, if an improvement project has been overlooked, a new evaluation may be justified.
Local Roads: Local governments may evaluate roads under their jurisdiction for STAA access. Trucking companies often request that local governments evaluate roads to their facilities. When a local government approves STAA access on a local road, before final approval, Caltrans must also approve the State highway intersection or ramp connecting to the local road.
Guidelines: For TA application guidelines and further discussion, see the web page: "Terminal Access Application Procedures" or call Caltrans Headquarters at (916) 654-5741.
The route networks developed out of a series of federal and State legislative acts, outlined below.
Federal STAA: In 1982, the federal government passed the Surface Transportation Assistance Act (STAA). This act required states to allow longer trucks as described in the table above on the "National Network."
AB 866: In 1983, California passed Assembly Bill (AB) 866 to implement the STAA provisions. AB 866 also increased the "California Legal" vehicle length from 60 to 65 feet and its width from 8.0 to 8.5 feet. Caltrans then evaluated State highways, and designated as "Terminal Access" those State highways with geometric standards high enough to accommodate STAA trucks.
SB 2232: In 1986, California passed Senate Bill 2232 which increased the maximum KPRA length from 38 feet to 40 feet for trailers with two or more axles. SB 2232 also directed Caltrans to determine which State highways could not safely accommodate trucks with a 40-foot KPRA length. In December 1989, Caltrans completed the report to the Legislature, "Truck Kingpin-To-Rear Axle Length State Highway System Evaluation." The report states that, of the 15,166 miles comprising the State Highway System, 3,364 miles cannot accommodate a 40-foot KPRA length, and 3,185 miles cannot accommodate a 38-foot KPRA length. Those route segments that cannot accommodate a 40-foot KPRA were designated "Advisory." (See section "California Legal Truck Routes" for more information on Advisory Routes.)
Engineering Basis: Caltrans performed engineering analyses to designate State routes. The engineering analyses focused on a vehicle characteristic called offtracking. Offtracking is the tendency for rear tires to follow a shorter path than the front tires when turning. Offtracking is the primary concern with longer vehicles, because rear tires may clip street signs, or drive onto unpaved shoulders, walkways, or bike lanes, or cross the centerline on a curve, creating a safety hazard for adjacent and oncoming traffic.
The following trade organizations may be good sources of information and networking:
California Trucking Association
American Trucking Associations
Caltrans Legal Truck Size & Weight Work Group
General number (916) 654-5741
E-mail: Legal Truck Access Branch.
Return to the Caltrans "Legal Truck Access Branch" page.