§ 15-3-3 Street design.
(A) Minimum required right of way widths.
(1) Major streets and highways, as required by current approved city, county or state standards.
(2) Collector streets as indicated by current approved city standards.
(3) Local streets as indicated by current approved city standards; 60 feet full street right of way may be required adjacent to park and school sites.
(a) Cul de sac streets shall terminate in a circular right of way 45 feet in radius with a three foot utility easement around the turnaround. The Department may approve an equally convenient form of turning and backing areas where extreme conditions justify.
(b) Dead end streets will not be approved except in locations designated by the Department as necessary to future extension in development of adjacent lands. In any case, a dead end street extending 200 feet or more shall provide by easement a temporary turning circle with a 40 foot radius or other acceptable design to accomplish adequate access.
(4) Marginal access or frontage streets as required by city standards.
(5) Alleys 16 feet wide, if single family residential on both sides; 20 feet wide, if abutting, multiple family, commercial or industrial districts. Alley intersection and sharp changes in alignment shall be avoided, but where necessary, corners shall be cut off 15 feet on each side to permit safe vehicular movement. Dead end alleys shall be prohibited. All half alleys shall have a minimum width of 12 feet.
(6) Private access ways as required by city standards.
(B) Grades.
(1) Maximum. Major streets as determined by the City Engineer.
(a) Collector streets: 7%.
(b) Local residential streets: 15%; all over 12% have a maximum length of 600 feet.
(2) Minimum. Concrete or asphalt streets with concrete gutters:
(a) Desirable 0.40%; Minimum 0.15%;
(b) Concrete or asphalt streets without gutters: Minimum 0.35%.
(3) Exceptions. Where rigid adherence to these standards causes unreasonable or unwarranted hardship in design or cost without commensurate public benefit, exceptions may be made by the Board upon review and recommendation of the City Engineer.
(C) Vertical curves.
(1) Major streets as determined by the City Engineer.
(2) Collector and local streets: minimum length, 100 feet, except in cases approved by the City Engineer.
(D) Horizontal alignment.
(1) Major streets as determined by the City Engineer.
(2) When tangent centerlines deflect from each other more than ten degrees and less than 90 degrees, they shall be connected by a curve with a minimum centerline radius of 500 feet for collector streets or 100 feet for local streets.
(3) Between reverse curves there shall be a tangent section of centerline not less than 100 feet long for a local street, as required by the City Engineer for collector and major streets.
(4) Streets intersecting a major street shall do so at a 90 degree angle; intersections of local streets shall not vary from 90 degrees by more than 15 degrees.
(5) Street jogs with centerline offsets of less than 125 feet shall be prohibited except when approved by the City Engineer. Under special circumstances where local streets intersect major streets, the City Engineer may require minimum centerline offsets of 400 feet.
(6) Local streets intersecting a collector street or major street shall have a tangent section of centerline at least 150 feet in length measured from the right of way line of the major street; except that no such tangent is required when the local street curve has a centerline radius greater than 400 feet with the center located on the major street right of way line. Where topographic conditions make necessary other treatment to secure the best overall design, these standards may be relaxed by the Board upon the recommendation of the City Engineer.
(7) Street intersections with more than four legs and Y type intersections where legs meet at acute angles shall be avoided; provision of T type intersections for local streets shall be encouraged.
(8) At local street intersections, property line corners shall be rounded by circular arc, said arc having a minimum tangent length and/or radius of 12 feet. A 16 foot by 16 foot triangle shall be provided at each corner of the intersection of two major streets; a 14 foot by 11 foot triangle at each corner of the intersection of two collector streets or as approved by the City Engineer.
(9) Collector streets shall intersect the major streets at the midsection corners or as otherwise approved.
(10) Local streets which are primary access to a subdivision shall intersect major streets at the quarter mile corners or as otherwise approved.
(11) Marginal access road openings to major streets, at a local street intersection, shall have a minimum 30 foot wide separation island between the major street traffic lanes and marginal access road, which shall be provided within the major street right of way.
(12) Marginal access roads shall not intersect a major street nor a collector street. (Prior Code, § 15-3-3)