(a) General. Street design shall conform to the standards set forth in A Policy on Geometric Design of Highways and Streets as published by AASHTO, the city's subdivision ordinance, Standard Specifications for Roads and Structures as published by the NCDOT, Roadway Design Manual as published by the NCDOT and the requirements outlined herein.
(b) Pavement and right-of-way widths.
(1) Minimum street widths are shown in the city's subdivision ordinance and the standard details. The city may require additional widening and related work as deemed necessary to provide for the safety and quality of roadway for the traveling public. The widths shall not be less than the following taken from the city's ordinance:
Rural | Minimum Right-of-Way, Feet |
Principal Arterial Freeways | 350 |
Other Freeways | 200 |
Minor Arterial | 100 |
Major Collector | 100 |
Minor Collector | 70 |
Local Road | 60 |
Urban | Minimum Right-of-Way, Feet |
Major thoroughfare other than freeway and expressway | 100 |
Minor thoroughfare | 80 |
Neighborhood street | 60 |
Cul-de-sac* | |
* The distance from the edge of the pavement of the turnaround to the right-of-way line shall not be less than the distance from the edge of the pavement to the right-of-way line on the street approaching the turnaround, as seen in Detail R.4.06 in the Appendix at the end of this chapter. | |
The subdivider will only be required to dedicate a maximum of 100 feet of right-of-way. In cases where over 100 feet of right-of-way is desired, the subdivider will be required only to reserve the amount in excess of 100 feet. In all cases in which right-of-way is sought for an access controlled facility, the subdivider will only be required to make a reservation.
(2) Widths for street and road classifications other than local shall be as required by the thoroughfare plan. Width for local roads and streets shall be as follows:
Road Type | W/Curb and Gutter Feet | W/O Curb and Gutter |
Local residential | 26 | 22 w/6 foot shoulder |
Residential collector | 34 | curb & gutter required |
Cul-de-sac | 60 foot radius | 60 foot radius |
(3) Cul-de-sac.
a. Permanent dead end streets are prohibited except when required by extreme topography, water or other natural features. When permitted, no dead end street shall be longer than 500 feet or provide access to more than 12 lots. Measurement shall be from the point where the center line of the dead end street intersects with the center of a through street to the center of the turnaround of the cul-de-sac.
b. Cul-de-sacs should not be used to avoid connection with an existing street or to avoid the extension of an important street.
(4) Bridges. Bridges shall be designed in accordance with NCDOT requirements and shall be subject to the approval of the city.
(5) Alleys.
a. The right-of-way width of an alley shall be 20 feet and the pavement width shall be 12 feet.
b. Deadend alleys shall be avoided where possible, but if unavoidable, shall be provided with adequate turnaround facilities at the deadend as may be recommended by the Planning Board and approved by the City Council.
c. Alleys shall be required to serve lots used for commercial and industrial purposes except that this requirement may be waived where other definite and assured provision is made for service access.
(c) Grades.
(1) Unless necessitated by exceptional topography and approved by the city, street grades shall meet grades included within the subdivision ordinance and shall not exceed 12%, nor be less than ½% , on any street, unless specific conditions are met within the subdivision ordinance.
(2) Grades approaching intersections shall not exceed 5% for a distance of not less than 100 feet from the right-of-way of such intersection unless otherwise approved by the city.
(3) All changes in street grade shall be connected by vertical curves of at least 100 feet, or calculated by use of Standard Detail R-4.07. (See Appendix at the end of this chapter.)
(4) Sharp alignment or grade changes shall be avoided.
(d) Radii of curvature.
(1) Where a street centerline deflection of more than five degrees occurs, a curve shall be introduced with the minimum centerline radius as shown in Standard Detail R-4.07.
(2) At intersections, all streets and commercial driveways shall be rounded with an edge of pavement or face of curb radii not less than the following:
a. Thoroughfares 50 feet
b. Collectors 40 feet
c. Residential 30 feet
(e) Tangents. A centerline tangent of not less than 100 feet shall be provided between reverse curves on all streets. Reverse curves on super-elevated streets shall have a sufficient centerline tangent to accommodate entry and exit run-out, but not less than 100 feet.
(f) Sight triangle.
(1) A sight triangle easement shall be provided at all intersections. No obstructions 30 inches higher than the elevation of the roadway's centerline intersection shall be allowed in the sight triangle.
(2) Sight triangle easements shall not be less than 10 feet by 70 feet. The 10-foot dimension shall be the setback from the right-of-way of the major street, and the 70-foot dimension shall be measured along the right-of-way of the major street.
(3) Sight triangle distances shall be increased by the city if appropriate for traffic conditions and speed limits.
(4) Sight triangle easements shall be shown on the final plat for the developed tract.
(g) Pavement design.
(1) The pavement design thickness shown in the Standard Details shall be considered as the minimum design requirements.
(2) If soil conditions and/or projected traffic volumes warrants, the city may require a pavement design in excess of the minimum requirements.
(3) If the Design Engineer believes that a more economical pavement design may be provided without sacrificing the structural integrity or 15-year design life of the pavement, an alternate pavement design based on actual soil support values as determined by California Bearing Ratio (CBR) or other acceptable method may be proposed. All design data, sealed by a Professional Engineer licensed by the State of North Carolina must be submitted to the city for review and approval.
(h) Curb and gutter, sidewalks.
(1) Curb and gutter, where required, shall be standard 30-inch combination curb and gutter unless otherwise approved by the city. Upon the approval of the city, 24-inch curb and gutter may be permitted.
(2) Sidewalks shall be a minimum of 5 feet wide. The minimum thickness of a sidewalk shall be 4 inches except where the sidewalk crosses a driveway, in which case it shall be 6 inches thick. Sidewalks shall have a uniform slope perpendicular to the curb of not greater than 1/4-inch per foot toward the roadway. The utility strip between the sidewalk and the back of curb shall not slope less than ½ inch per foot or greater than 3/4-inch per foot toward the roadway.
(3) All sidewalks and ramps shall meet the current Americans With Disabilities Act (ADA) requirements.
(Ord. of 11-7-16, No. 10-16)