Truck Route Classifications

INTRODUCTION

What is the purpose of this fact sheet? This fact sheet is an overview of truck route classifications in California. Its purpose is to enhance communication between Caltrans, the trucking industry and local governments regarding legal truck size.

HISTORY

How were the route classifications created? Route classifications 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 larger trucks on the "National Network," which is comprised of the Interstate system plus the non-Interstate Federal-aid Primary System. "Larger trucks" includes (1) doubles with 28.5-foot trailers, (2) singles with 48-foot semi-trailers and unlimited kingpin-to-rear axle (KPRA) distance, (3) unlimited length for both vehicle combinations, and (3) widths up to 102 inches. 

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 classified 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 "Route Classifications" for more information on Advisory Routes.)

What is the STAA Network? The National Network (NN), Terminal Access (TA) and Service Access routes together make up the "STAA Network." These are the routes that allow STAA trucks.

What was the engineering basis for the classifications? Caltrans performed engineering analyses to classify 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 shoulders, walkways, or bike lanes, or cross the centerline on a curve, creating a safety hazard for adjacent and oncoming traffic.

TRUCK SIZES

What are the dimensions for the truck classifications? "California Legal" trucks must be no larger than 14 feet high, 102 inches wide and 40 feet long if a single vehicle, and 65 feet long if a combinaton vehicle. An overall length exception to 75 feet is given for truck tractor - semitrailer - trailer combinations (doubles) if each trailer is no more than 28 feet six inches long. Length requirements also depend on the route traveled, as discussed below in the section "Route Classifications."

The four major truck size categories are:

For a graphic illustration of length dimensions of California Legal (black truck) and STAA (green truck) vehicles with both single trailers and doubles, see this web page: Truck Map Legend.

ROUTE CLASSIFICATIONS

Which routes can trucks use? All federal and State highways are assigned route classifications.

STAA trucks are limited to the National Network, Terminal Access routes, and Service Access routes (STAA Network). "California Legal" trucks can use the STAA Network and California Legal routes. The route classifications in California are listed below.

National Network (Federal): The National Network (NN) is primarily comprised of the National System of Interstate and Defense Highways, for example I-10, I-5, and I-80. STAA trucks are allowed on the NN.

Terminal Access (State, Local): Terminal Access (TA) routes are portions of State routes, or local roads, that can accommodate STAA trucks. TA routes allow STAA trucks to (1) travel between NN routes, (2) reach a truck's operating facility, or (3) reach a facility where freight originates, terminates, or is handled in the transportation process.

Terminal Access Signing: A Terminal Access symbol sign must be posted in advance of the ramp or intersection to an authorized TA route. This information sign (#G66-56) is white-on-blue with the letter "T" on the back of a truck. For information on signing TA routes, see the 2006 California Manual on Uniform Traffic Control Devices (MUTCD), Part 2 at: www.dot.ca.gov/hq/traffops/signtech/mutcdsupp/pdf/camutcd/CAMUTCD-Part2.pdf, starting on page 2D-29.

Service Access (State, Local): STAA trucks may exit the National Network to access those highways which provide reasonable access to terminals and facilities for purposes limited to fuel, food, lodging, and repair, when that access is consistent with safe operation. The facility must be within one road mile of an exit from the National Network and that exit must be identified by signage.

Service Access Signing: A Service Access symbol sign is displayed on the NN route in advance of the ramp or intersection of an authorized service access road. This information sign (#G66-55) is white-on-blue with the letter "S" on the back of a truck. For more information on signing service routes, see the Caltrans web site mentioned above.

California Legal (State): California Legal routes are State routes that allow California Legal-size trucks. STAA trucks are not allowed on these routes because of limiting geometrics, such as sharp curves and/or lack of turn-around space.

California Legal - Advisory (State): California law allows regulatory prohibition of a 38-foot KPRA or greater where posted in black-on-white. However, many California Legal routes cannot safely accommodate California Legal-size trucks with a KPRA less then 38 feet, due to limiting geometrics such as sharp turns and highway width. Although California Legal trucks may travel on these segments, the driver is still legally responsible for unsafe offtracking, such as crossing the centerline or driving on shoulders, curbs and sidewalks.

California Legal - Advisory Signing: "Advisory" route segments are posted with black-on-yellow warning signs as shown below.

Special Restrictions (Federal, State, Local): Some route segments have special restrictions on certain trucks or loads, such as gross weight, number of axles, or hauling of flammable materials or explosives. Restrictions on federal or State routes are illustrated on the on-line truck map, and also listed on the Caltrans Truck Route List. Both are posted on this web site: http://www.dot.ca.gov/hq/traffops/trucks/truckmap/. For vehicles complying with the restrictions (for example, vehicles not carrying explosives), the route classification, in most cases, reverts back to that of the adjacent route segments.

What about local roads? Local roads governed by cities or counties that allow STAA trucks are posted with the Caltrans TA sign. If a STAA truck needs to travel off the NN and TA routes, the driver may want to contact the city and/or county public works department in advance to determine which roads are available.

Are any local maps available? Currently, Sacramento County and San Joaquin County have STAA maps for their jurisdictions, as well as the City of Sacramento and the City of Roseville. All four maps are available as links on the web site listed above. As additional local maps become available, they will be posted to our web site.

Can I request that a route classification be changed? Caltrans classified all State routes in 1989 with an engineering analysis. However, improvement projects may change the highway geometrics and may justify a new evaluation. Also, local governments may evaluate roads under their jurisdiction to consider allowing STAA trucks. For application guidelines and further discussion, go to the on-line fact sheet "Terminal Access Application Procedures" or call Caltrans Headquarters at (916) 654-5741.

CALIFORNIA VEHICLE CODE

Where can I read more of California law? Legal requirements for vehicles are included in the California Vehicle Code (CVC). The CVC can be accessed on the Internet by two methods:

1. To view the CVC, start at the site www.leginfo.ca.gov and click on the [California Law] button. To view the Vehicle Code, check the box by "Vehicle Code" and click on the [Search] button. For length requirements, scroll down and click on sections 35400-35414.
2. To search the CVC, follow the same steps, but type in a key word before clicking on the [Search] button.

TRUCK NETWORK MAP

Caltrans' Office of Truck Services provides a statewide truck network map showing federal and State routes. Each route segment is color-coded by classification.

Is the map on-line? Yes, the map is posted on the Internet. It is kept continuously updated, and can be viewed at this web site: http://www.dot.ca.gov/hq/traffops/trucks/truckmap/.

How may I obtain the printed map? The printed "Truck Networks Map" dated October 2002 can be ordered at no charge by contacting Caltrans at (916) 654-5741. There are currently 11 amendments to the printed map. The amendments are posted on-line at the web site above.

Are the route classifications also available on a list? Yes. The "Truck Network Route List" includes each route segment with beginning and ending locations and postmiles. This list is also available on the web page "California Truck Network Map" described directly above. Or you may request a copy from the Caltrans staff listed below.

ORGANIZATIONS

The following trade organizations may be good sources of information and networking:

California Trucking Association 3251 Beacon Blvd West Sacramento, CA 95691 (916) 373-3500 Web site: www.caltrux.org

American Trucking Associations 2200 Mill Road Alexandria, VA 22314-4677 (703) 838-1700 Web site: www.trucking.org

---

CONTACTS

Caltrans Legal Truck Size & Weight Work Group
Casey Robb
Manuel Fonseca
General number (916) 654-5741
E-mail: Truck Size & Weight Unit.

Return to the Caltrans "Office of Truck Services" page.

Revised 10/15/08.