The specifications contained herein are the minimum allowable and, at the discretion of the Boone County Highway Department, may be increased when warranted.
(A) Residential driveway.
(1) Minimum driveway width: 12 feet.
(2) Maximum driveway width: 20 feet.
(3) Minimum culvert diameter: 12 inches.
(4) Minimum culvert length: 30 feet.
(5) Culvert material:
(a) Reinforced concrete/end sections; and
(b) Corrugated metal pipe/end sections (14-ga. minimum).
(6) Culvert elevation: minimum top of pipe six inches lower than edge of roadway.
(7) Minimum site distance: 200 feet each direction.
(8) Minimum distance to nearest intersection: 50 feet.
(9) Material: shall be a paved or compacted aggregate #53 or #73 stone surface type to match county road section (except agricultural field entrance may be dirt or gravel).
(10) Angle of intersection with county road: 60-degree minimum.
(11) Minimum design and sketches for residential driveways and mailbox approaches shall be shown.
(12) The mailbox turnout detail is the required specification of the Highway Department, but to the limitations of some county road right-of-way these specifications can be changed accommodate the mailbox approach with a minimum specification of 3-foot setback from the edge of the roadway to the face of the mailbox. This is on approval of the Boone County Highway Department.
(B) Multi-family, commercial and industrial driveways.
(1) Minimum driveway width: 20 feet.
(2) Maximum driveway width: 40 feet.
(3) Minimum culvert diameter: 12 inches.
(4) Minimum culvert length: 32 feet.
(5) Culvert material:
(a) Reinforced concrete/end sections; and
(b) Corrugated metal pipe/end sections (14 ga. minimum).
(6) Culvert elevation: Top of pipe at least eight inches lower than the edge of roadway.
(7) Minimum sight distance: 200 feet, each direction on local road 300 feet for collector or arterial routes.
(8) Minimum distance to nearest intersection: 200 feet.
(9) Minimum distance to nearest driveway: 200 feet.
(10) Material: paved surface or compacted aggregate #53 or #73 stone surface type to match county road section.
(11) Angle of intersection with county road: 70-degree minimum.
(12) Acceleration and decelerating tapers: ADT greater the 1,000 and/or road is designated as collector or arterial route.
(13) Minimum design and sketches for multi-family, commercial and industrial driveways shall be as shown.
(C) Residential, commercial and industrial subdivisions and planned unit development entrances.
(1) Minimum driveway width: 20 feet.
(2) Maximum driveway width: 60 feet.
(3) Minimum culvert diameter: 12 inches.
(4) Minimum culvert length: 32 feet.
(5) Culvert material:
(a) Reinforced concrete/end sections; and
(b) Corrugated metal pipe/end sections (14 ga. minimum).
(6) Culvert elevation: top of pipe at least eight inches lower than edge of roadway.
(7) Minimum sight distance: 200 feet each direction on local road, 300 feet for collector or arterial routes.
(8) Minimum distance to nearest intersection: 200 feet.
(9) Minimum distance nearest driveway: 200 feet.
(10) Material: paved or compacted aggregate #53 or #73 stone surface type to match county road section.
(11) Angle of intersection with county road: 70-degree minimum.
(12) Acceleration and decelerating tapers with right turn storage lane: ADT greater than 1,000 and/or road is designated as collector or arterial route.
(13) Passing blisters: all routes designated by the Boone County Thoroughfare Plan or designated as collector or arterial routes.
(14) Minimum design and sketches for residential, commercial and industrial subdivisions and planned unit development entrances shall be as shown.
(D) Location of driveways.
(1) Driveway shall be located so as to result in no undue interference with, nor hazard to, the free movement of normal vehicular traffic and so that areas of traffic congestion will not be created on the roadway. In accordance with this principle, driveways shall be located where the roadway alignment and profile are favorable and there are no sharp curves, steep grades and sight distance restrictions. To the extent feasible within the frontage limits, and driveway along the roadway. Application may be denied if adequate sight distance cannot be obtained.
(2) For property tracts with a sizeable frontage on the roadway, the driveway location and arrangement will be governed by the position of the improvements. However, where driveways are provided to predominantly unimproved areas, they shall be located to the best advantage with regard to the roadway alignment, profile and sight distance conditions.
(3) Where a driveway is provided to a commercial establishment, the road right-of-way and the adjacent borders shall be reasonably clear.
(E) Number of drives.
(1) The number of driveways should be a minimum to adequately serve the needs of the abutting property. Commercial frontages of less than 200 feet are limited to one driveway. Normally, not more than two driveways shall be allowed into any single property tract or business establishment. When more than two driveways on one frontage are necessary to facilitate operations, the minimum distance between drives should be 400 feet. A property which has more than one frontage on a roadway may be allowed one driveway per frontage.
(2) Where there are several adjacent roadside establishments, each with limited frontage or where there is a probably of the development, consideration shall be given to constructing a frontage road for several driveways so as to reduce the number of separate connections to the highway. Frontage roads that parallel the highway shall be allowed access points at minimum intervals of 500 feet. Frontage roads should be set back from the county roadway in such a manner as to allow adequate storage for entering and existing traffic.
(F) Joint driveways. An approach to a driveway that serves adjacent property owners may be allowed. However, the application shall be jointly prepared and submitted by the property owners.
(G) Driveway approach grade. The profile grade of the approach from the edge of the existing lane pavement shall slope down and away at the same rate as the roadway shoulder grade. It shall be constructed in manner that no surface water will drain onto the roadway.
(H) Sight distance. To the extent feasible within the frontage limits, any driveway should be located at a point of optimum sight distance along the roadway.
(I) Drainage.
(1) The applicant shall provide drainage information and show that there are no adverse affects to drainage patterns in the vicinity caused by the new drive.
(2) Culvert pipes shall not be sized smaller than structures upstream from their location.
(3) Culvert pipes sized for driveways shall follow design frequencies for a ten-year design storm.
(4) All pipes shall have end sections. End sections may be either concrete or metal and shall comply with the following details
(Ord. 94-9, passed 5-16-1994)