2013 Forest Service Outdoor Recreation Accessibility Guidelines (FSORAG)

3.1.3.2 Running Slope (Grade) of Driveways.

The running slope of driveways shall be no more than 1:12 (8.33 percent) for no more than 50 feet (15 m).

Exception 1. A running slope of up to 1:10 (10 percent) for driveways is permitted for up to 30 feet (9 m).

Exception 2. For alteration only, not new construction, if exception 1 of section 3.1.3.2 cannot be met because one or more conditions for exception in section 1.1 exist, a running slope of no more than 1:10 (10 percent) is permitted for no more than 50 feet (15 m).