Either type 1 or type 2 drives (Fig. 2.49) may be used in urban areas. If used in urban areas, the radius and flare dimensions may be reduced so that the apron does not extend past the back of the sidewalk, or past the right-of-way line if there are no sidewalks. The desirable minimum radius for type 1 drives, when the through highway is curbed, is 15 ft (4.6 m).
Three methods are shown in Fig. 2.50 for designing driveways between the curb line and sidewalk to provide for turning vehicles. Other designs may be used if they are approved for use by the local governmental agencies responsible for maintenance of the project. Additional details are shown in Fig. 2.51 when the tree lawn is less than 6 ft (1.8 m). Residential drives on curbed streets should use a dropped curb as shown in section B-B of Fig. 2.50.
