(a) Generally. The specifications set forth in this section are hereby declared to be the standards and general plan adopted by Council for the width and location of all highways, streets and alleys which may hereafter be platted or accepted in the City. However, roads under the jurisdiction of the County Road Department shall conform to the road and right-of-way standards and policies of the Department, and roads under the jurisdiction of the City shall conform to the standards set forth in the Street and Traffic Plan of the Comprehensive Development Plan.
(b) Layout. The layout of proposed streets shall provide for the continuation of existing streets in surrounding areas and/or shall conform to a plan for the neighborhood approved by the Planning Commission in cases where topographical or other conditions preclude the continuation of existing streets. In general, such streets shall be of a width as great as that of the street so extended. Due consideration shall be given to traffic safety. Minor residential streets shall be laid out so as to discourage their use by through traffic. Due consideration shall also be given by the subdivider to the attractiveness of the street layout in order to obtain the maximum livability and amenity of the subdivision. Consideration shall also be given to the proposed use of the subdivision, and proper allowance shall be made in industrial subdivisions for potential and existing railroad rights of way as conditions will permit. Any intersection occurring on a street which crosses a railroad track shall be not less than 400 feet from the nearest railroad right of way. Greater distances may be required if it is deemed necessary for safety, approach gradients or future grade separations.
(c) Major Thoroughfares. Where a subdivision abuts or contains an existing or proposed major thoroughfare, the Planning Commission may, at its discretion, require the construction of marginal access streets, reverse frontage lots with provision for screen planting contained in a nonaccess reservation along rear property lines with a minimum width of fifteen feet or with side lot lines parallel to major thoroughfares, deep lots with rear service alleys or other treatment which the Commission considers essential for adequate protection of residential lots and for separation of through and local traffic.
(d) Private Streets and Alleys. Private streets and alleys shall not be permitted. All streets and alleys shall be dedicated to the public.
(e) Dedication of Half-Streets. The dedication of half-streets will not be permitted where a subdivision adjoins undeveloped property, except where one-half of major streets are sixty feet or greater in width as appearing on the Comprehensive Development Plan. Wherever there already exists a dedicated and recorded half-street or half-alley on an adjoining plat, the other half must be dedicated on the proposed plat to make the street or alley complete.
(f) Street Jogs. Street jogs with centerline offsets of not less than 125 feet should be avoided.
(g) Cul-de-Sacs. Where required for the full and best utilization of the property, cul-de-sacs may be utilized. The maximum permissible length of a cul-de-sac shall be 500 feet measured from the right-of-way line of the nearest intersecting street to the farthest point on the right-of-way line of the cul-de-sac. Each cul-de-sac shall be provided at its closed end with a turnaround having a diameter at the outside of the roadway pavement of at least eighty feet and a property line diameter of at least 120 feet for residential streets and 150 feet for industrial streets. The remaining portion of the cul-de-sac shall have a right-of-way width of at least sixty feet. The straight portion of the right of way shall be joined to the circular portion of the right of way by circular curves with radii of not less than fifty feet.
(h) Dead-End Streets. Dead-end streets shall be defined as streets which will not or cannot be extended through to another street in the future. Normally, such streets shall be deemed permanent dead-end streets and will not be approved if they exceed 400 feet in length as measured from the right-of-way line of the nearest cross street to the center of the cul-de-sac. Every permanent dead-end street shall be provided at the closed end with a turnaround having an outside roadway diameter of at least seventy feet and a street property line diameter of at least ninety-nine feet. However, under specific existing conditions, where topographic conditions indicate that a hardship would be caused if this requirement were strictly enforced, and where an exception to this regulation might serve the best interests of the City, an extension of a dead-end street, to a total length of not more than 600 feet, may be granted.
(i) Alleys. Continuous alleys having a minimum width of twenty feet will be required in the rear of all local business and commercial lots, except that this requirement may be waived by the City Engineer where other definite and assured provision is made for service access, such as off-street loading and parking consistent with and adequate for the use proposed.
A diagonal cut-off shall be made at all acute and right-angle intersections of alleys sufficient to provide an inside turning radius of thirty feet.
Alleys shall not be approved in residential areas unless they are deemed necessary because of topography or other exceptional circumstances.
(j) Street Names. Street names which might cause confusion with names of existing streets in or near the City shall not be permitted. Streets that will be continuations of existing streets shall be called by the same names of such existing streets. All names shall be approved by the Planning Commission, with final approval by Council.
(k) Building Lines and Set-Back Lines. Building lines shall conform to the Zoning Code.
(l) Right-of-Way Width. The minimum right-of-way width shall be sixty feet. Greater right-of-way widths for major thoroughfares and collector streets may be required by the Planning Commission or the County Road Department.
(m) Horizontal Alignment. Centerlines of pavement shall coincide with centerlines of rights of way, except for irregular right-of-way widths.
(n) Street Grades. Profiles shall be required on all streets. The minimum gradient allowed shall be 0.4 percent and the maximum gradient allowed shall be 6.0 percent. Variances must be approved by the City Engineer, with the purpose for the variance clearly indicated.
(o) Street Curvature. The minimum horizontal centerline radii of curved local streets shall be 200 feet. Greater radii may be required for principal streets having through traffic. A minimum fifty-foot tangent shall be introduced between reverse curves on streets of a sixty-foot right of way. Greater tangents shall be required on streets of a greater right of way. Modifications of these requirements may be made by the City Engineer, where compliance with them may serve no good purpose.
(p) Street Alignment. When street lines deflect from each other by more than ten degrees in alignment, the centerlines shall be connected by a curve with a minimum radius of 500 feet for major arterial streets, 300 feet for collector streets and 150 feet for local or minor streets. Between reverse curves, on minor streets, there shall be a minimum tangent distance of 100 feet, and on collector and arterial streets, 200 feet.
(q) Street Intersections.
(1) The intersection of more than two streets at one point shall be avoided. Exceptions to this requirement shall be considered individually by the Planning Commission and shall be authorized only where there is no alternative.
(2) Streets shall intersect at ninety degree angles or closely thereto, and in no case at less than eighty degree angles.
(3) Except on arterials and certain collectors, "T" type intersections shall be used where practical.
(4) No street intersection shall be located closer than 200 feet to another intersection.
(5) Intersections shall be provided with a minimum slope to facilitate drainage. This minimum slope shall be carried back 150 feet each way from the intersection, measured from the centerline of the intersected street. An allowance of three percent maximum intersection grade will be permitted.
(6) There shall be a clear vision zone at all corners of intersecting roads or road junctions, consisting of a triangular area defined by the point of intersection of the right-of-way lines and the line drawn between two points extended along such right-of-way lines a distance of twenty-five feet from the point of intersection. Within such area, no obstruction to vision, excluding existing topography, shall be permitted from a height of two feet to eight feet above the centerline elevation of abutting streets, except that not more than one tree with a trunk of not more than thirty inches in diameter and clear of any branches for such heights may be located within such area. This paragraph shall not prohibit the requirement of a greater clear vision zone where such is necessary in view of permitted traffic turning movements, existing and anticipated traffic volumes, traffic speeds, intersection configurations, geographic and topographic conditions or other unique characteristics which may require a greater clear vision zone.
(r) Surface Drainage. The preferred plan for yard drainage shall provide for drainage from the rear of a lot to the front of a lot with a minimum grade of one percent and a maximum grade of three percent (FHA Type A).
If it is found to be essential to the economic development of substantial portions of a project, an easement at the rear of the lot may be below the building grade. In this event, the grade shall be not less than one percent nor more than three percent and the grade from the house to the street shall be not less than one percent with the building grade being not less than twelve inches above the street grade. Grades in excess of three percent shall be subject to the approval of the City Engineer, after recommendation from the Planning Commission.
Where a low easement is essential to the economical development of major portions of the project, the longitudinal grade of such easement shall be not less than 0.4 of one percent and the length of run of such longitudinal easement shall not exceed 500 feet of continuance drainage, with not more than 100 feet of such drainage being upstream from an angle point in the easement.
Where required by the City Engineer, a four-inch drainage tile shall be provided for easement drainage, with such tile laid in a trench backfilled with pea gravel or approved bankrun gravel. The depth of the grade and outlet for such tile is subject to City approval.
(s) Access to Streets Across Ditches. Subdividers shall provide access to all proposed streets across watercourses or ditches in a standard manner as approved by the City Engineer.
(t) Acceleration and Deceleration Lanes. Acceleration, deceleration and passing lanes shall be provided at the intersections of a minor street with a major thoroughfare, as required by the highway authority having jurisdiction.
(u) Local or Minor Streets. Such streets shall be so arranged as to discourage their use by through traffic.
(v) Relation to Topography. Streets shall be arranged in proper relation to topography so as to result in usable lots, safe streets and reasonable gradients.
(w) Marginal Access Streets. Where a subdivision abuts or contains a major thoroughfare, the City may require:
(1) Marginal access streets approximately parallel to and on each side of the right of way; or
(2) Such other treatment as it deems necessary for the adequate protection of residential properties and to afford separation of through and local traffic.
(x) Corner Radii. Curb corners shall be rounded or cut back to provide for a curb radius of not less than twenty feet. Special cases due to existing conditions will be considered individually on the basis of safety and overall design.
(y) Streets in Relation to Railroads. Whenever a subdivision adjoins or includes a railroad right of way, a street shall be placed parallel to the railroad to intercept streets tending to otherwise cross the tracks. Any intersection occurring on a street which crosses the railroad track shall not be less than 400 feet from the nearest railroad right of way. Greater distances may be required if deemed necessary for safety, approach gradients or future grade separations.
(z) Sidewalks. Sidewalks shall be required on both sides of the street. Sidewalks shall be sized and surfaced in accordance with Chapter 1248.
(Ord. 260. Passed 12-7-77.)