Local agencies set engineering design standards for the width and slope (or “grade”) of driveways that access the public street system. Most public agencies require a paved driveway between the property line and the street. Asphalt or concrete are typical driveway surfacing materials.
A driveway approach or apron is the area between the public street and the property line. In urban areas with curbs along the public street, 10 percent is a typical maximum longitudinal slope for a residential driveway approach. The slope of a driveway approach should not exceed 2 percent where it crosses a public sidewalk.
Behind the property line, the slope of a paved residential driveway is usually governed by site topography and drainage needs. Minimum slopes of about 2 percent allow for proper drainage. Maximum slopes are typically limited to about 15 percent, but local agency design standards differ widely.
Avoid sharp changes in grade to reduce the chance of damage to a vehicle’s undercarriage. Steep driveway grades impede vehicle and pedestrian access in areas subject to snow and ice. More restrictive grade standards generally are set for commercial and other higher volume driveways. Less restrictive design standards are set for unpaved low-volume driveways, such as agricultural access to a public road.