§ 150.062 DESIGN STANDARDS.

   (A)   General. In order to provide for streets of suitable location, width, and improvement to accommodate prospective traffic and afford satisfactory access for police, firefighting, snow removal, sanitation, and street maintenance equipment, and to coordinate street location in order to achieve a convenient system and avoid undue hardships to adjoining properties, the following design standards for streets are hereby required. (Street classifications may be indicated in the Comprehensive Plan, thoroughfare plan, or on the official map; otherwise, they shall be determined by the Commission.)

   (B)   Street surfacing and improvements. After sewer and water utilities have been installed by the developer, the applicant shall construct curbs and gutters and shall surface or cause the roadways to be surfaced to the widths prescribed in these regulations. Said surfacing shall be of such character as is suitable for the expected traffic and in harmony with similar improvements in the surrounding areas. Types of pavement shall be as determined by the City Engineer. Adequate provision shall be made for culverts, drains, and bridges. All street pavement, shoulders, drainage improvements, and structures, curbs, turnarounds, and sidewalks shall conform to all construction standards and specifications adopted by the Commission, City Engineer, or the city and shall be incorporated into the construction plans required to be submitted by the developer for plat approval.

   (C)   Excess right-of-way. Right-of-way widths in excess of the standards designed in these regulations shall be required whenever, due to topography, additional width is necessary to provide for adequate and stable earth slopes. Such slopes shall not be in excess of three to one.

   (D)   Railroads and limited access highways. Railroad rights-of-way and limited access highways where so located as to affect the subdivision of adjoining lands shall be treated as follows.

      (1)   In residential districts, a buffer strip at least 25 feet in depth in addition to the normal depth of the lot required in the district shall be provided adjacent to the railroad right-of-way or limited access highway. This strip shall be part of the platted lots and shall be designated on the plat: “this strip is reserved for screening. The placement of structures hereon other than earth berms, walls, fences, and other landscape screening devices approved by the Commission is prohibited.”

      (2)   In districts zoned for business, commercial, or industrial uses, the nearest street extending parallel or approximately parallel to a railroad shall, wherever practical, be at a sufficient distance therefrom to ensure a suitable depth for commercial or industrial sites.

      (3)   Streets parallel to a railroad when intersecting a street which crosses the railroad at grade shall, to the extent practicable, be at a distance of at least 150 feet from the railroad right-of-way. Such distance shall be determined with due consideration of the minimum distance required for future separation of grades by means of appropriate approach gradients.

   (E)   Intersections.

      (1)   Streets shall be laid out so as to intersect as nearly as possible at right angles. A proposed intersection of two new streets at an angle of less than 75 degrees shall not be acceptable. An oblique street should be approximately at right angles for at least 100 feet therefrom. Not more than two streets shall intersect at any one point unless specifically approved by the Commission.

      (2)   Proposed new intersections along one side of an existing street shall, wherever practicable, coincide with any existing intersection on the opposite side of such street. Street jogs with center line offsets of less than 150 feet shall not be permitted except where the intersected street has separated, dual drives, without median breaks at either such intersection. Where local streets intersect with arterials, their alignment shall be continuous. Intersections of arterials shall be at least 800 feet apart.

      (3)   Minimum curb radius at the intersection of two local streets shall be at least 20 feet, and minimum curb radius at an intersection involving a collector street shall be at least 25 feet. Alley intersections and abrupt changes in alignment within a block shall have the corners cut off in accordance with standard engineering practice to permit safe vehicular movement.

      (4)   Intersections shall be designed with a flat grade wherever practical. In hilly or rolling areas, at the approach to an intersection, a leveling area shall be provided having not greater than a 2% grade at a distance of 60 feet, measured from the nearest right-of-way line of the intersection street.

      (5)   Where any street intersection will involve earth banks or existing vegetation inside any lot corner that would create a traffic hazard by limiting visibility, the developer shall cut such ground and/or vegetation (including trimming trees) in connection with the grading of the public right-of-way to the extent deemed necessary by the City Engineer to provide an adequate sight distance.

      (6)   The cross-slopes on all streets, including intersections, shall be 3% or less.

   (F)   Bridges. Bridges of primary benefit to the applicant, as determined by the Commission, shall be constructed at the full expense of the applicant without reimbursement from the city. The sharing of expense for the construction of bridges not of primary benefit to the applicant, as determined by the Commission, will be fixed by special agreement between the city and the applicant. Said cost shall be charged to the applicant pro-rata as the percentage of his or her land developed and so served.

   (G)   Typical rural cross-sections for major streets.

   (H)   Typical urban cross-sections for major streets.

   (I)   Design standards for streets.

Street Type			Min. Width R-O-W (ft.)	Min. Pvmnt. Width (1) (ft.)	Min. Side Ditch Width (ft.)	Min. Shoulder Width (ft.)	Max Grade (%)	Min. Radius of Curve (ft.)	Min. Length of Tangent (3) (ft.)	Min. Sight Distance (ft.)	Min. Corner Radius (4) (ft.)	Min. Turnaround (5) (ft.)
Urban Cross-Section	Resident. (6)	Place	40	18	N/A	N/A	7.5	100	100	200	20	80/60
		Local Street	50	26	N/A	N/A	7.5	100	100	200	20	100/80
		Collector	60	33	N/A	N/A	7.0	100	150	240	25	N/A
	Nonresident.	Local Street	60	30	N/A	N/A	6.0	200	200	200	40	160/140
		Collector	70	40	N/A	N/A	6.0	200	200	240	40	N/A
	Arterial	Secondary	70	44	N/A	N/A	(2)	(2)	(2)	(2)	(2)	N/A
		Primary	80	54	N/A	N/A	(2)	(2)	(2)	(2)	(2)	N/A
		Divided Primary	100	2-24	N/A	N/A	(2)	(2)	(2)	(2)	(2)	N/A
Rural Cross-Section	Resident. (6)	Place	50	18	10	6	7.5	100	100	200	20	100/76
		Local Street	60	26	10	6	7.5	100	100	200	20	100/76
		Collector	65	33	10	6	7.0	100	150	240	25	N/A
	Nonresident.	Local Street	65	30	10	6	6.0	200	200	200	40	160/140
		Collector	75	40	10	6	6.0	200	200	240	40	N/A
	Arterial	Secondary	80	24	22	6	(2)	(2)	(2)	(2)	(2)	N/A
		Primary	120	48	28	8	(2)	(2)	(2)	(2)	(2)	N/A
		Divided Primary	150	2-24	31	10	(2)	(2)	(2)	(2)	(2)	N/A
Notes to table: (1)   Curb and gutter is in addition on urban cross-sections (combined two-foot minimum on each side). (2)   As required by the Local Government Engineer and/or State Highway Commission. (3)   Between reverse curves. (4)   Measured at curb on urban cross-sections, at pavement edge on rural cross-sections. Transitional curve into the turnaround within cul-de-sac: residential - 50 feet; nonresidential - 100 feet. (5)   Diameter, measured at edge of right-of-way/edge of pavement, or back to back or curb on urban cross-sections. (6)   Includes subdivisions for uses permitted in residential districts as a matter of right or through special exception.

 

   (J)   Standards applied to all streets.

      (1)   Minimum grade: 0.5%;

      (2)   Minimum block length: 400 feet (1,000 feet between collectors along arterials);

      (3)   Maximum block length: 2,600 feet;

      (4)   Maximum cul-de-sac length: 800 feet;

      (5)   Maximum length of temporary dead-end street: 1,000 feet; and

      (6)   Minimum length of vertical curves: 100 feet, but not less than 20 feet for each percent of algebraic difference in grade.

(Ord. 5-1992, passed 7-21-1992)