19.10.4 Curb Ramp
Curb ramps that access accessible parking spaces are not required to include detectable warnings unless they also serve pedestrian street crossings. The designer has the option of providing detectable warnings or not.
provides an examples of the curb ramp options.

Figure 19-41: Perpendicular Parking Access Aisles, Showing A Curb Ramp With Flares (Top) And A Parallel Curb Ramp (Bottom).