Parking spaces for the handicapped shall be located as close as possible to elevators, ramps, walkways and the accessible entrance they serve. They shall be as level as possible with paved surface slopes not exceeding 1:48 ( 1/4 inch per foot) in any direction. Such spaces, when possible, shall be located so that persons in wheelchairs or using braces or crutches are not compelled to wheel or walk behind parked cars, and, where applicable, curb ramps shall be provided to permit handicapped persons access from the parking area to the sidewalk.