E.2 - Design Requirements.

E.2.1

Alleys. Alleys shall have a minimum right-of-way width of twenty (20) feet and a minimum paving width of eighteen (18) feet edge to edge. Alleys shall be paved with reinforced Portland cement concrete or hot mix asphalt concrete and constructed to city specifications. All utilities to be located in the alley shall be in place before the alley is paved.

E.2.2

Intersections.

1.

Streets shall be designed to intersect as nearly as possible at right angles, and in no case intersect at an angle of less than 75°. An oblique street should be curved approaching an intersection and should be at a right angle to the other street for a least one hundred (100) feet from the intersection. No more than two (2) streets shall intersect at any point unless specifically approved by the City Engineer. Where these conditions are determined to be unavoidable, other design compensations may be required (e.g. setback lines further from the right-of-way than usually required, rounding or cutting of corners, or relocation of an intersection).

2.

Proposed new intersections along an existing street shall, wherever practicable, coincide with existing intersections on the opposite side of the existing street. Any centerline offsets shall meet the requirements of Table E-1. Proposed new intersections shall also meet the intersection/spacing requirements of Table E-1. No offsets shall be allowed for extension of existing or new arterial streets.

3.

The curb line for urban streets or edge of pavement shall be rounded with a curve of radius R varying with the interior angle of the adjacent lot corner as specified in Table E-2. The property line at street intersections shall be rounded with a curve of radius R varying with the interior angle of the adjacent lot corner as specified in Table E-3.

4.

Alleys shall be treated as local streets.

E.2.3

Driveway Access. Driveway access to single and two-family lots should be from collector (Type C) or minor residential streets. Driveway access to single and two-family lots with frontage on more than one (1) street shall be prohibited from existing or proposed major arterial Type (A+) through major collector (Type C+) streets if one (1) frontage of the lot is on a collector (Type C) or minor residential street. Driveway access to single and two-family lots with frontage on more than one (1) street and all frontages are on existing or proposed major arterial Type (A+) through major collector (Type C+) streets shall be from the street with the lowest classification (i.e., from a major collector (Type C+) street rather than from a major arterial Type (A+) street). When driveway access is required from an existing or proposed major arterial Type (A+) through major collector (Type C+) street, the driveway shall be constructed so as to provide a paved area for vehicles to turn around on-site and exit the lot without having to be backed into the public right-of-way. A note or a one-foot "no access easement" shall be placed on the plat where driveway access is prohibited.

E.2.4

Street Right-of-Way and Paving Width Requirements.

1.

Urban streets. The dimensions shown in Table E-4 represent minimum requirements for dedicated right-of-way widths or permanent ingress/egress easements and are required of all subdivisions platted within the city and its ETJ. These minimums may be increased or decreased by the City Engineer where conditions warrant. Such conditions include but are not limited to intersections which will require turning lanes, where oversize storm drains, water lines, or sewer lines are located adjacent to the street, and unusual topographic conditions. Determinations of street classification shall be made by the City Engineer and the city planner and shall be based on the needs of the subdivision, the comprehensive plan, the existing street classification system map and the MTP.

2.

Rural streets. Minor residential and collector streets built as rural streets without curb and gutter or sidewalks shall have a minimum right-of-way width of sixty-four (64) feet and a minimum hot mix asphaltic concrete pavement width twenty-four (24) feet edge to edge with four-foot compacted base shoulders or ribbon curb on each side of the street. The depth of the compacted base shoulders shall be equal to the depth required for the street. Rural streets shall have roadside drainage ditches with 4H:1V front and back slopes. Rural streets shall require greater right-of-way widths or drainage easements shall be platted on the adjacent lots in order to maintain the required side slopes on the drainage ditches and contain the ditches in the right-of-way or easement. When drainage easements are dedicated in lieu of right-of-way, they shall not be included in any yard setback requirements of the zoning ordinance. Design speed, minimum centerline radius, minimum grade, maximum grade, stopping sight distance, and number of lanes shall be the same as those for urban streets in Table E-4. These minimums may be increased or decreased by the City Engineer where conditions warrant. Such conditions include but are not limited to intersections which will require turning lanes, where oversize storm drains, water lines, or sewer lines are located adjacent to the street, and unusual topographic conditions. Streets classified as Major Collector Type C+ or greater that are located in or adjacent to rural type subdivisions shall be constructed as such in accordance with subsection 17.5-93(d)(10). Determinations of street classification shall be made by the City Engineer and the city planner and shall be based on the needs of the subdivision, the comprehensive plan, the existing street classification system map and the MTP.

3.

General. Existing streets and permanent ingress/egress easements will be required to meet these minimum requirements unless exempted by the City Engineer. Additional right-of-way or ingress/egress easements may be required by the City Engineer where the conditions warrant such. Additional right-of-way shall be dedicated for subdivisions of two or more lots adjacent to existing boundary streets not meeting the minimum standards of this chapter. Permanent ingress/egress access easements will be required to meet the minimum requirements for streets provided for by this chapter unless exempted by the City Engineer.

It is further provided that on plats for subdivisions in the ETJ, the developer/owner may subdivide property as required herein by dedicating permanent ingress/egress access easements to a dedicated right-of-way. The dedication shall reflect that the permanent ingress/egress access easement is in lieu of a public dedicated right-of-way. The dedication shall also place the purchaser on notice that no governmental entity shall ever be responsible to repair, maintain or reconstruct said permanent ingress/egress access easements. The dedication shall state that the expenses for the repair, maintenance, or reconstruction of the permanent ingress/egress access easements will be the responsibility of the homeowners association (name shown on the plat), organization or individual homeowner. Permanent ingress/egress easements shall be required to meet the minimum requirements for streets in this chapter unless exempted by the City Council.

E.2.5

Vertical Curves. Vertical curves shall be designed and constructed to provide the minimum stopping sight distance required in Table E-4.

E.2.6

Special Purpose Streets.

1.

Marginal access streets. A marginal access street may be approved by the city for subdivisions with frontage on an arterial street if it is determined that such a street is needed to provide separation of through and local traffic. If a marginal access street is provided, it shall be separated from the arterial street by a distance of at least twenty-six (26) feet.

2.

Culs-de-sac. A street terminating in a cul-de-sac shall be no more than six hundred (600) feet in length as measured along the street's centerline from the centerline of the last intersection to the radius point of the cul-de-sac. This minimum may be increased by the City Engineer where conditions warrant. The street shall have a minimum right-of-way width and minimum paving width as required for minor residential streets. The cul-de-sac (turnaround) shall have a minimum pavement radius of forty-five (45) feet as measured from the center to the back of curb for urban and industrial streets and edge of pavement for rural streets and a minimum right-of-way radius of fifty-four (54) feet as measured from the center to the right-of-way line for urban and industrial streets and sixty-one (61) feet for rural streets. The minimum right-of-way radius for rural culs-de-sac shall be increased or drainage easements shall be platted on the adjacent lots as necessary to accommodate drainage.

3.

Dead end or stubbed streets. Dead end or stubbed streets shall be avoided unless future extensions of the street are planned. When a street extension into an undeveloped area is planned, the developer may be required to build the street and construct a temporary turnaround with a paved surface at the end with proper barricading and warning signs, or post a security bond for the full cost of future construction of the street plus reasonable inflation. It will be the responsibility of the developer to secure adequate easement or right-of-way for any temporary turnarounds. Dead end or stubbed streets shall not exceed one thousand (1,000) feet in length. A paved turnaround may be waived for dead end or stubbed streets which extend only the depth of an average lot and has no more than one (1) lot fronting on each side.

4.

Service road. Service roads shall be treated as an arterial for intersection spacing, curb returns, and property line returns.

TABLE E-1
(See Section 17.5-93(d)(4)(c))
MINIMUM INTERSECTION SEPARATION AND OFF-SET REQUIREMENTS FOR NEW STREETS

New Street	Existing Street
	Major Arterial Type A+	Major Arterial Type A	Major Arterial Type B+	Major Collector Type B	Major Collector Type C+	Collector Type C	Minor/ Residential
Major Arterial Type A+	1,000 ft.	N/A	N/A	N/A	N/A	N/A	N/A
Major Arterial Type A	1,000 ft.	700 ft.	N/A	N/A	N/A	N/A	N/A
Minor Arterial Type B+	1,000 ft.	700 ft.	500 ft.	N/A	N/A	N/A	N/A
Major Collector Type B	1,000 ft.	700 ft.	500 ft.	400 ft.	N/A	N/A	N/A
Major Collector Type C+	1,000 ft.	700 ft.	500 ft.	400 ft.	300 ft.	N/A	N/A
Collector Type C	1,000 ft.	700 ft.	500 ft.	400 ft.	300 ft.	300 ft.	N/A
Minor Residential	1,000 ft.	700 ft.	500 ft.	400 ft.	300 ft.	150 ft.	150 ft.
N/A indicates that the new street must be continuous with no off-set.

 

TABLE E-2
[See Section 17-93(d)(4)c.]
MINIMUM INTERSECTION CURB RETURNS

Interior Angle of Property Lines	Intersection of Local or Collector With Collector or Local Collector	Intersection of Local or Collector With Arterial	Intersection of Arterial with Arterial
105° - 85°	15 ft.	25 ft.	35 ft.
85° - 75°	20 ft.	30 ft.	50 ft.
The pavement return radius for intersections of streets constructed to rural street standards shall be equal to the curb return radius required for the intersection of two arterials.

 

TABLE E-3
[See section 17.5-93(d)(4)c.]
PROPERTY LINE INTERSECTION RETURNS

Interior Angle of Property Lines	Intersection Type
	Locals and Collectors	Arterial
105° - 85°	15 ft. Parkway = R	25 ft.
85° - 75°	20 ft. - Parkway = R	40 ft.
The property line return radius for intersections of subdivisions constructed to rural street standards shall be equal to the property line return radius required for the intersection of two arterials.

 

TABLE E-4
[See Section 17.5-93(d)(6)a., b. and Section 17.5-93(d)(7)]
URBAN STREET DESIGN STANDARDS

Section Type	Design Speed	Min. Center Line Radius	Min. Grade *	Max. Grade *	Stopping Sight Distance	Traffic Lanes	Parking Lanes	Residential Driveway Access	Median	Street Width	Right- of-Way
Major Arterial Type A+	45 mph	1200 ft.	0.35%	7.0%	400 ft.	6 @ 12 ft.	None	Restricted	Raised @ 10 ft. back to back	90 ft. back to back	120 ft.
Major Arterial Type A	40 mph	1,000 ft.	0.35%	7.0 %	325 ft.	6 @ 12 ft.	None	Restricted	Painted @ 14 ft.	94 ft. back to back	110 ft.
Minor Arterial Type B+	35 mph	700 ft.	0.35%	9.0%	250 ft.	4 @ 12 ft.	None	Restricted	Painted @ 14 ft.	70 ft. back to back	90 ft.
Major Collector Type B	30 mph	500 ft.	0.35%	11.0%	200 ft.	4 @ 11 ft.	None	Restricted	Painted @ 12 ft.	60 ft. back to back	80 ft.
Major Collector Type C+	30 mph	375 ft.	0.35%	12.0%	200 ft.	4 @ 11 ft.	None	Restricted	None	48 ft. back to back	70 ft.
Collector Type C	30 mph	300 ft.	0.35%	14.0%	200 ft.	2 @ 11 ft.	2 @ 8 ft.	Permitted	None	48 ft. back to back	60 ft.
Minor Residential	30 mph	100 ft.	0.35 %	14.0%	200 ft.	2 @10 ft.	2 @ 6 ft.	Permitted	None	36 ft. back to back	54 ft.

 

* Can exceed in secondary access ways upon approval of the Public Works Director in consultation with the City Engineer and Fire Chief. Sec. 17.5-112. - Blocks.

E.2.7

Block Dimensions. Block size and shape shall be conditioned by the type and use of the proposed development and shall be compatible with the size and shape of blocks in neighboring developments:

1.

Blocks in residential areas should be at least two hundred (200) feet, but not more than one thousand two hundred (1,200) feet, in length and at least one hundred (100) feet, but not more than three hundred fifty (350) feet, in depth. Deviation from these general requirements shall be considered on a case by case basis. The city planner and the City Engineer shall make a recommendation to the Planning and Zoning Commission and City Council.

2.

Appropriate block dimensions in a commercial or industrial development are relative to land use and shall be considered on a case by case basis. Effect on the flow of traffic and safety precautions necessitated by the development shall be primary factors in determining appropriate block length. The city planner and the City Engineer, shall make a recommendation to the Planning and Zoning Commission and city Council.

E.2.8

Pedestrian Walkways. The city may require the dedication of pedestrian and bicycle access to parks, schools, playgrounds, shopping centers, or other community facilities. The city planner and the City Engineer, shall make a recommendation to the Planning and Zoning Commission and City Council. Where the parks and recreation plan calls for bike trails, a minimum of fifteen (15) feet shall be dedicated. Other pedestrian access easements shall be a minimum of ten (10) feet.