California Department of Transportation

Service Access Routes


Definition: Federal and state law allows STAA vehicles to exit the National Network (NN) for a distance of one road mile to access food, fuel, lodging, and repair services, provided the exits are identified.

Identification: The exits could be identified by maps, lists, or signs. Caltrans policy is to identify Service Access roads with signs posted in advance of the ramp or intersection.

Signage: The Service Access sign is a white-on-blue information sign with the letter "S" on the back of a truck, as illustrated below:

Sign Code: G66-55 (CA)

STAA Trucks: The 1982 federal Surface Transportation Assistance Act (STAA) allowed larger trucks on the National Network. These larger trucks are called "STAA vehicles." (For more details on truck sizes and routes, see the web page Truck Size & Routes.)

STAA Access Routes: STAA vehicles can use the NN, and can exit the NN only where a "T" signs is posted for Terminal Access, or an "S" sign is posted for Service Access.

Services: A Service Access route may provide food, fuel, lodging, and/or repair; however, at least two of these three services -- food, fuel, and lodging -- must be present before a sign will be posted.


Federal Law: The 1982 federal STAA required reasonable access to facilities for food, fuel, repairs, and rest. In 1990, federal regulations expanded truck access from one-half mile to one mile off the NN. The Code of Federal Regulations, Title 23, Section 658.19 (a) states "No State may enact or enforce any law denying reasonable access to vehicles with dimensions authorized by the STAA between the NN and... facilities for food, fuel, repairs, and rest." Section (d) states "No State may enact or enforce any law denying access within 1 road-mile from the National Network... except for specific safety reasons... ."

State Law: In 1983, AB 866 implemented the federal STAA in California. The California Vehicle Code, Section 35401.5 states that STAA vehicles may use highways off the National Network "...which provide reasonable access to terminals and facilities for purposes limited to fuel, food, lodging, and repair when that access is consistent with the safe operation of the combinations of vehicles and when the facility is within one road mile of identified points of ingress and egress... ."


Applications: In the mid-1980s, Caltrans evaluated ramps and intersections on the NN and posted Service Access signs. However, a new evaluation may be justified at certain locations, because of new services or improvement projects that change the highway geometrics. For application guidelines, follow the steps on the web page Terminal Access Application Procedures.

Criteria for Approval: The California Manual on Uniform Traffic Control Devices (CA MUTCD) specifies the requirements for Service Access routes. See the current CA MUTCD Part 2: Signs.