California Department of Transportation

Terminal Access Application Procedures


STAA Truck: A STAA truck is a truck with a 48-foot semitrailer, an unlimited overall length, and an unlimited kingpin-to-rear-axle (KPRA) distance. STAA trucks were made legal on the National Network by the 1982 federal Surface Transportation Assistance Act (STAA).

California Legal Trucks: A California Legal truck has an overall maximum length of 65 feet, and a maximum KPRA of 40 feet.

National Network (NN): A network of federal highways that includes primarily interstates.

Terminal Access Route: Federal law requires that states allow STAA trucks reasonable access to terminals. In the 1980's, California evaluated all State routes and allowed STAA vehicles on those routes that could accommodate them. These are called Terminal Access (TA) routes. State routes are continuously re-evaluated as improvement projects are completed. Local governments also evaluate local roads for STAA access to create local TA routes.

More Info: For more details on truck sizes and legislative history, see the Caltrans web pages: Truck Lengths & Routes -- Quick Guide" and Truck Size & Routes.


Caltrans classified all State routes in the 1980's with an engineering analysis. However, improvement projects may change the highway geometrics and may justify a new evaluation. To apply for a Terminal Access designation on a State route, you may send your request to the appropriate Caltrans District Truck Staff. You may also call Caltrans Headquarters at (916) 654-5741 for more information.


Local governments may evaluate roads under their jurisdiction to consider allowing STAA trucks. Caltrans suggests that applicants and local governments follow the guidelines below.


Some local governments are not familiar with these procedures. However, Caltrans can provide guidance to local agencies re. route analysis and signage, if needed.

  1. Applicant sends a request to the local agency, and sends copies of that request to the Caltrans District Truck Staff and to other local agencies along the proposed route, if any. (There is no application form. A letter will suffice. Be sure that the letter includes all pertinent information, including the desired route, the highway exit, streets, and address of the terminal.)
  2. Local agency acknowledges receipt of the request and identifies the time frame for response. (Local agency and Caltrans must act on request within 90 days of receipt.)
  3. Local agency sends a copy of the request and an acknowledgement letter to the appropriate Caltrans District Truck Staff.


  1. Local agency and Caltrans analyze the affected highway segments, intersections and interchanges under their respective jurisdictions, to determine whether both facilities can safely accommodate STAA vehicles. The Caltrans Highway Design Manual, Topic 404, is recommended as a guide for analyzing for STAA access.
  2. If the proposed TA route passes through more than one local jurisdiction, each affected local agency analyzes their route segment.
  3. If one end of the proposed local route dead ends (does not connect with another TA route), then that end point must have an adequate turn-around area, and that area must be accessible to all STAA trucks 24 hours per day. If the new route dead ends at a private terminal, the terminal facility must provide the 24-hour turn-around area for all STAA trucks, and permission for access must be provided in writing to the agency that is approving the route, e.g. Caltrans or the local government.


Access is denied. Local agency notifies the applicant by letter that access is denied and sends a copy of the letter to the Caltrans District Truck Staff. The process ends here, unless an improvement project is initiated to correct the problem.


  1. The local agency sends the Caltrans District Truck Staff a letter stating that "the local roads and intersections on the proposed local Terminal Access route meet all geometric criteria for STAA trucks" as required by the 2012 California Manual on Uniform Traffic Control Devices (CA MUTCD), Page 568. The CA MUTCD defines "geometric criteria" as "the STAA vehicle can stay in its lane without encroaching into the adjacent or opposing lane." The letter must be signed by a responsible authority representing the local jurisdiction.
  2. If the proposed TA route passes through more than one local jurisdiction, each affected local agency sends a letter to Caltrans as described in #1 above.
  3. The Caltrans district sends a copy of the letter(s) to Caltrans HQ Office of Traffic Engineering, Legal Truck Access Branch.
  4. The local agency notifies the applicant that access is granted and sends a copy of the letter to the Caltrans District Truck Staff.


If access is granted, the Caltrans Terminal Access signs (G66-56) must be installed:

  1. The local agency installs Terminal Access signs (G66-56) along local routes as trailblazers. At locations where the TA route ends (at the 24-hour turn around areas), a G66-56 sign must be installed with an "End" sign (M4-6).
  2. In addition to the required TA signs, the local agency is also encouraged to produce a map or a listing of local TA routes that can be posted on the local government website, and linked on the Caltrans website at:
  3. The local government notifies Caltrans that the local TA signs are installed.
  4. After the local TA signs are installed, Caltrans installs TA signs on the State route indicating the approved exits leading to the new local TA route. The signs should be posted as soon as possible; the timeline for posting signs on the State route can be discussed with the Caltrans District Truck Staff who will place the sign order with District Maintenance.


Reasonable Access: Code of Federal Regulations, Title 23, § 658.19 states, "Reasonable access. (a) No State may enact or enforce any law denying reasonable access to vehicles with dimensions authorized by the STAA between the NN and terminals and facilities for food, fuel, repairs, and rest. ... (h) States shall ensure compliance with the requirements of this section for roads under the jurisdiction of local units of government."

Process: Section 35401.5(d) of the California Vehicle Code (CVC) states, "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 terminal is considered any place of business, provided that it is a legal operation."

Geometric Criteria: 2012 California Manual on Uniform Traffic Control Devices (CA MUTCD), Page 568 states: "2. On Local Highways: • Signing of egress from a State Terminal Access route to a local Terminal Access route shall be done only if requested by the local jurisdiction and: a) the local jurisdiction has informed the Department in writing that the local roads and intersections on the proposed local Terminal Access route meet all geometric criteria* for STAA trucks and, b) the State highway ramp or intersection meets all geometric criteria for STAA trucks. *The geometric criteria involves using a STAA vehicle to design the intersection or ramp so that the STAA vehicle can stay in its lane without encroaching into the adjacent or opposing lane."

Sign Installation: The sign installation is required by law. The 2012 California Manual on Uniform Traffic Control Devices (CA MUTCD), Page 568 under "2. On Local Highways" states:

  • Local agency shall place G66-56(CA) signs at every critical decision point on the Terminal Access route, including a G66-56(CA) sign with END Auxiliary (M4-6) sign.
  • The State shall place a G66-56(CA) sign on the State route in advance of the ramp or intersection to the local Terminal Access highway.

CA MUTCD Update: Caltrans Traffic Operations Policy Directive #12-05, dated 12/21/12, strengthened and clarified the TA requirements in the 2012 CA MUTCD. These changes will be incorporated into the next edition of the CA MUTCD in 2014.

Basis for Denial: A request for a terminal route can be denied; however, the CVC Section 35401.5(d) states, "The denial of a request for access to terminals and services shall be only on the basis of safety and an engineering analysis of the proposed access route."

Time Limit: The CVC Section 35401.5(d) states, "If a written request for access has been properly submitted and has not been acted upon within 90 days of receipt by the Department or the appropriate local agency, the access shall be deemed automatically approved." However, the meaning of the term "act" may be open to interpretation; it may not necessarily mean that the final decision must be made during that time frame.

Access for All: When an application is successful, the road is opened to all trucks of the same type as the applicant. CVC Section 35401.5(d) states, "...the route shall be deemed open for access by all other vehicles of the same type regardless of ownership."


Off-Tracking: Caltrans performs engineering analyses that focus on a vehicle characteristic called "off-tracking." Off-tracking is the tendency for rear tires to follow a shorter path than the front tires when turning. Off-tracking is the primary concern with longer vehicles because rear tires may clip street signs, drive onto unpaved shoulders, walkways, or bike lanes, or cross the centerline on a curve, creating a safety hazard for adjacent and oncoming traffic.

Design Criteria: The STAA design vehicle and guidance for its use are included in the Caltrans Highway Design Manual, Topic 404. The STAA design vehicle has a 48-foot semitrailer. (Trucks with 53-foot semitrailers are also considered STAA trucks; however, trucks with the 53-foot semis are not used as a design vehicle as they are not the worst case for off-tracking due to their shorter wheelbase.)

Templates: The Highway Design Manual has templates for design vehicles, including STAA vehicles. Designers can print the templates and scale them as needed.

Software: Caltrans uses "AutoTurn" software which simulates the turning movements of slow-moving vehicles. AutoTurn is compatible with MicroStation and AutoCADD. AutoTurn is available from Transoft Solutions at this website: Other truck-turning software programs include "AutoTrack" at Savoy Computing Services Ltd at this website:, and "PathPlanner" at Simtra Aero Tech at this website:


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

E-mail: Legal Truck Access Branch.

Return to the Caltrans "Legal Truck Access Branch" page.

Revised 5/16/14.