2.7 Site Circulation Design

Site circulation design for GSA projects will vary greatly depending on the context, which can range from tight urban sites to suburban campuses or isolated rural settings. Yet the basic criteria remain the same in all situations: the site design should segregate, at a minimum, pedestrian access, vehicular access (including parking) and service vehicle access.

Security is an important consideration in site design. Refer to Chapter 8: Security Design for detailed criteria related to this matter.

Urban Site with Structured Parking
Service Traffic. Service dock access may be from an alley, from a below-grade ramp or from a site circulation drive. If large trucks are to service the facility, sufficient maneuvering space must be provided, and the service drive shall be screened as much as possible. It should always be separate from the access to the parking garage. Where possible, a one-way design for service traffic is preferable to avoid the need for large truck turning areas. The service area of the facility shall not interfere with public access roadways. See Chapter 3: Architectural and Interior Design for criteria on ramps and service areas.

Oakland Federal Building, Oakland, CA Bruce R. Thompson U.S. Courthouse and Federal Building, Reno, NV

Public Transportation. GSA encourages the use of public transportation among employees and visitors. The potential need for a bus stop should be considered early in the design of a GSA building in an urban setting and should be discussed with planners of the mass transit system. The project team should consider how to treat the orientation of the building and the site design and landscaping to encourage use of public transit and to address pedestrian traffic ‘desire lines’ between the building entrance and transit stops. Pedestrian Circulation. The project team should consider neighboring uses, existing pedestrian patterns, local transit, and the building’s orientation to anticipate pedestrian ‘desire lines’ to and from the building from off site. Designers should avoid dead ends, inconvenient routes, and the like and consider how people moving across the site might help to activate sitting areas, outdoor art, programmed events, etc. Drop-Off. If the security analysis determines it is feasible, a vehicular drop-off area should be located on the street nearest the main entrance and, site conditions permitting, also near the entrance to the child care center, if the project includes one. See GSA Child Care Center Design Guide (PBS-P140). Fire Apparatus Access Fire department vehicle access shall be provided and maintained to all new construction and alterations in accordance with the requirements of National Model Fire Code that is used, NFPA 241, and NFPA 1141.

Fire Apparatus Access Roads. The local fire department shall be consulted with regard to their specific requirements regarding the surface material of the access roadway(s), minimum width of fire lane(s), minimum turning radius for the largest fire department apparatus, weight of largest fire department apparatus, and minimum vertical clearance of largest fire department apparatus.

Vehicular Drives, Parking Lots and Service Areas
Entrance Drives. Follow local codes for entrance driveways within the right-of-way limits of city, county or State maintained roads.

Aerial Apparatus. Buildings or portions of buildings exceeding 30 feet in height from the lowest point of fire department vehicle access shall be provided with access roads capable of accommodating fire department aerial apparatus. Overhead utility and power lines shall not be within the aerial access roadway. In addition, at least one access road having a minimum unobstructed width of 26 feet shall be located within a minimum of 15 feet and a maximum of 30 feet from the building. Also, at least one side of all buildings shall be accessible to fire apparatus.

Surface Parking Lots. Parking stalls must be 2700 mm (9 feet) wide and 5400 mm (18 feet, 6 inches) long, with two-way aisles of 7300 mm (24 feet).Where possible, 90-degree parking should be used. Accessible parking spaces must be provided; these shall comply with the UFAS/ADA in quantity, location and size.

Internal islands for landscape planting should occupy no less than 10 percent of the total parking lot area. Curbs should be provided around the parking lot perimeter and around landscape islands.

The maximum combined gradient for parking lots should not exceed 5 percent.