(a) In rural areas, recommended maximum grade within the highway right-of-way is 10 percent for commercial driveways and 12 percent for residential driveways. In urban areas the recommended maximum grades are six and eight percent, respectively. Where special circumstances require driveway grades in excess of these recommended maximums, an engineering determination is necessary by the department to establish a safe profile design.

(b) All driveways shall be constructed to slope away from the edge of pavement at the same slope as the highway shoulder which normally varies in slope from one-half to one inch per foot. This slope shall be continued the full width of the shoulder or longer to avoid causing a bump or depression on the shoulder area.

(c) Whenever a change in a driveway grade occurs, the profile shall be rounded by connecting the two different grades with a smooth vertical curve such that a normal shoulder is carried through the driveway area. If possible, the low point of the driveway should be at or close to the center line of the highway ditch.

(d) Where a sidewalk is located close to the curb line and the driveway opening is to be provided by a depressed or cut curb, the sidewalk should be warped to conform to the driveway profile. One or both edges of the sidewalk may be depressed across the driveway providing the resulting sidewalk cross-slope does not exceed one-half inch per foot. A sidewalk grade shall not exceed 10 percent. In some cases, it may be necessary to discontinue the sidewalk across the driveway and construct a curb along each driveway edge. In such cases, provisions shall be made for the handicapped.

(e) Where curb cuts are made for the construction of driveways, the entire curb section shall be removed and replaced with a curb of one inch reveal. The removal of only the raised portion of the curb and paving over the broken section shall not be allowed. Cut curb ends shall be tapered from full height to one inch above ground level in a distance of approximately two feet. Where drainage is carried along the curb, the driveway shall be constructed with a short upgrade to prevent runoff from spilling into private property. Details of a curb cut are shown in section 125.19 of this Part.