The American Association of State Highway and Transportation Officials (AASHTO) is the organization of state departments of transportation that develops standards and guidance for highway, street and bridge design in the United States.
Established in 1914 and based in Washington, D.C., AASHTO publishes the technical policies that shape most public roads. Parking facilities borrow from its work for driveways, access roads and the vehicle dimensions used to check turns. Traffic control devices are governed separately by the MUTCD.
Publications that touch parking
- A Policy on Geometric Design of Highways and Streets, the Green Book, including standard design vehicles and turning paths. See design vehicle.
- LRFD Bridge Design Specifications, relevant to some ramps and structures that carry public roads.
- Roadside Design Guide, on barriers and roadside safety.
- Guidance on bicycle and pedestrian facilities.
Why parking designers use it
- Standard vehicle dimensions and turning radii for access roads, loading areas and ramps.
- Sight distance and driveway design where garages meet streets.
- Public agencies often require AASHTO-based design for access permits.
The Parkonomics view
AASHTO guidance was written for roads, not garages, so it is a starting point for parking design rather than the answer. Parking-specific design vehicles and geometry still matter more inside the structure.
Related terms: Design Vehicle, MUTCD, AutoTURN, Turning Bay, Parking Geometry, Stroad