(a) Conformity With Major Thoroughfare Plan or Planning Commission Recommendations. The arrangement, character, extent, width and location of major, secondary and minor streets or highways shall conform with the official Major Thoroughfare Plan for the City and with the provisions of this chapter. Streets not contained in the official Major Thoroughfare Plan shall conform to the recommendation of the Planning Commission based upon existing and planned streets, topography, public safety and convenience and proposed uses of land.
(b) Design and Arrangement.
(1) The arrangement of streets in new subdivisions shall make provision for the continuation of the principal existing streets in adjoining areas (or their proper projection where adjoining land is not subdivided) insofar as they may be deemed necessary for public requirements.
(2) The street and alley arrangement shall be such as not to cause hardship to owners of adjoining property when they plat their own land and seek to provide for convenient access to it. Residential streets shall be so designed as to discourage through traffic, but off-set streets should be avoided.
(3) The angle of intersection between minor streets and major streets should not vary by more than ten degrees from a right angle. All other streets should intersect each other as near to a right angle as possible, and no intersection of streets at angles of less than seventy degrees shall be permitted.
(4) Residential streets shall be designed to discourage through traffic which may otherwise use secondary or major highways, and whose origin and destination are not within the subdivision. Residential streets extending for considerable distances, parallel to any secondary or major street, should be avoided.
(c) Alignment.
(1) Vertical. For main thoroughfares, profile grades shall be connected by vertical curves of a minimum length equivalent to twenty times the algebraic difference between the rates of grade, expressed in feet per hundred. For secondary and minor streets and alleys, profile grades shall be connected by vertical curves of a minimum length equivalent to fifteen times the algebraic difference between the rates of grade, expressed in feet per hundred.
(2) Minimum horizontal. Radii of centerline curvature shall be as follows:
A. Main thoroughfares: twelve degrees, 475 feet.
B. Secondary thoroughfares: nineteen degrees, 300 feet.
C. Minor streets: twenty-eight degrees, 200 feet
D. Streets shorter than 500 feet: fifty-eight degrees, 100 feet.
A minimum fifty-foot tangent shall be introduced between reverse curves.
(3) Visibility.
A. The minimum vertical visibility, measured four and one-half feet eye level to a tail light eighteen inches above ground level, shall be as follows:
1. 500 feet on main thoroughfares.
2. 300 feet on secondary thoroughfares.
3. 200 feet on minor streets.
4. 100 feet on streets shorter than 500 feet.
B. The minimum horizontal visibility shall be as follows:
1. 500 feet on main thoroughfares, measured on the centerline.
2. 300 feet on secondary thoroughfares, measured on the centerline.
3. 100 feet on all other streets, measured on the centerline.
(d) Street and Alley Width.
(1) The width of all major thoroughfares shall conform to the width designated on the Major Thoroughfare Plan of the City and of the County.
(2) The minimum width of minor streets in single-family and two-family districts shall be fifty feet, except that where there are unusual topographical or other physical conditions, the Planning Commission may require a greater or lesser width for a minor street. The minimum width of minor streets serving multiple dwellings shall be sixty feet.
(e) Cul-De-Sacs. Each cul-de-sac shall be provided with a turn-around having a minimum right-of-way radius of fifty feet. The outside of the road surface within the turn-around right of way shall have a minimum radius of forty feet.
(f) Dead-End Streets. Streets designated to be dead-ended permanently shall not be permitted. Any dead-end street of a temporary nature, if longer than 200 feet or fronted by existing lots, shall have a surfaced turning area equal in diameter to the width of such street at its termination.
(g) Half-Streets. Dedication of half-streets shall be discouraged. Where there exists a dedicated or platted half-street or alley adjacent to the tract being subdivided, the other half shall be platted if deemed necessary by the Commission.
(h) Alleys. Alleys should be avoided in single-family or two-family districts. They may, however, be required in multiple dwelling developments, where they should have a minimum width of twenty feet. Alleys are required in the rear of all commercial and industrial lots if no other provisions are made for adequate service access or for parking. The rights of way of such alleys shall not be less than twenty feet, and dead-end alleys shall not be permitted.
(i) Street Grades. No street grade shall be less than one-half percent, nor exceed the following percentages, with due allowances for reasonable vertical curves:
Main or arterial thoroughfares 5%
Secondary thoroughfares 6%
Minor streets 8%
Secondary thoroughfares 6%
Minor streets 8%
(j) Street Names. Where new names are required for new streets in unincorporated areas, the names shall meet the approval of the County Engineer.
(Ord. 2133. Passed 10-18-59; Ord. 85-61. Passed 12-18-85.)