§ 5.2. Streets.

The street standards of this section shall apply to all new streets built within a public right-of-way. Streets in all new major subdivisions, commercial developments and industrial developments shall meet the requirements below. Lots adjacent to streets that have been platted but not constructed may not be developed until new streets are built to these requirements.

5.2.1 The purpose of this section is to ensure that the arrangement, design, character, extent, width, grade, and location of all streets: (1) shall conform to the Town's Comprehensive Plan; and (2) shall be considered in their relationship to existing and planned streets, topographic conditions, public convenience, safety, and in their appropriate relation to the proposed uses of the land immediately served by such streets and those areas outside of the subdivision which may need to be served by such streets in the future; and (3) provide safe, convenient, and comfortable routes for walking, bicycling, and public transportation that encourage increased use of these modes of transportation, enable convenient travel as part of daily activities, improve the public welfare by addressing a wide array of health and environmental problems, and meet the needs of all users of the streets, including children, older adults, and people with disabilities. To the maximum extent possible, local streets shall be laid out so as to discourage vehicular traffic through residential neighborhoods, while still providing adequate emergency service.

5.2.2 To provide information on the capacity of streets serving new development, the Community Development Department may require the applicant to conduct a traffic impact study or other infrastructure capacity analysis that assesses the impacts of the proposed use on existing roads, intersections, and vehicular, pedestrian, and bicycle circulation patterns, and that sets forth mitigation measures to eliminate or substantially reduce such impacts.

Table 5.2: Required Street Dimensions
Street Type	Local Streets			Collector Streets		Arterial Streets
	Residential		Commercial	Urban	Rural	Secondary		Primary Urban/Rural
	Urban	Rural				Urban	Rural
Minimum ROW	50'	50'	60'	64'	64'	86'	86'	106'
Minimum travel lane width:
Two-way street	10' (2 lanes)	10' (2 lanes)	12' (2 lanes)	11' or 12'* (2 or 4 lanes)	11' (2 lanes)	12' (2 or 4 lanes)	12' (2 or 4 lanes)
One-way street	16'	16'	16'	N/A	N/A	N/A	N/A
Curb/gutter widths	6"/18"	*	6"/18"	6"/18"	*	6"/18"	*
Shoulder width		4'			6'		8'
Turn lane width*	10'	10'	12'	12'	12'	12'	12'
Median				*		*	*
Parking lane width (includes gutter)	7'		9'	7'*
Bicycle lane width				4'	4'*	4'	4'*
Sidewalk width* (Verge width)	5'		6' or 8'*	5' (4')	5'* (4')	6' (4')	6'* (4')
Maximum cul-de-sac length	400'	1,000'	400'
Maximum grade	12% (14%<300')	12% (14%<300')	7%	10% (12%<500')	10% (12%<500')	7%	7%	6%
Design speed	25 mph	25 mph	25 mph	25 mph	25 mph	30 mph	30 mph	35 mph

 

 

*As required (see text). Blank space = Not Required. Article II contains definitions and examples of local, collector, and arterial streets.

5.2.3 Selection of the appropriate street type and street dimensions from Table 5.2 shall be determined in accordance with standards that follow in this subsection, subject to approval of the Public Works Director. Choices given in Table 5.2 are examples and not exhaustive.

A)

Applicable Street Types by Zoning District.

1)

Rural streets (local, collector, and arterial) are only allowed in the Rural (Ru) zone district and Large Lot Overlay zones.

2)

Urban (local, collector, and arterial) street types are required in all other zone districts, except where a commercial street type is required, as stated in subsection (3).

3)

The local commercial street type is required in the commercial zone districts C-HD, C-Lt, C-Hwy.

B)

Right-of-Way (ROW) and Easements.

1)

Street ROW must be sufficient to accommodate functions in addition to the movement of automobiles, including shoulders, graded slopes, drainage, sidewalks, verge, and/or bicycle lanes.

2)

Additional easements or rights-of-way must be provided for pedestrian walkways and bicycle paths that are not adjacent to roadways.

3)

ROW width for one-way roads may be reduced to 40 feet upon approval of a dimensional adjustment (see Section 6.3.18(B)(5)).

C)

Travel Lanes, Turn Lanes, Medians.

1)

The number of travel lanes shall be determined based on the street type and function. A traffic study may be required.

2)

One-way streets may be allowed, subject to a traffic impact study, for local residential and commercial streets.

3)

Turn lanes, medians and wider travel lanes may be required by the Public Works Director or as indicated by a traffic impact study.

D)

Curb/Gutter and Shoulders.

1)

A 6" barrier curb with an 18" gutter is required on all urban street types. Roll curbs or alternatives to curbs may be allowed on rural streets or on urban streets with approval of the Public Works Director, if adequate drainage measures are provided and adequate separation between street and sidewalk is provided for pedestrian safety.

2)

Rural streets may be constructed without curb and gutter subject to the approval of the Public Works Director. Streets without curb and gutter shall have shoulders with stabilized surfacing. For collector streets where Average Daily Traffic (ADT) exceeds 2,000, a shoulder width of eight feet is required.

E)

Parking Lanes.

1)

Parking lanes shall generally be required on both sides of local urban residential, local commercial, and urban collector streets in order to provide adequate and convenient on-street parking, and to help reduce speeds.

2)

On urban collector streets, minimum parking lane width is seven feet unless wider lanes are indicated by a traffic impact study.

3)

On rural residential or collector streets, off-street parking spaces may be provided adjacent to roll curbs within the right-of-way, with a minimum width of eight feet between the curb and sidewalk (if present).

F)

Bicycle Lanes and Paths.

1)

Bicycle lanes or paths are not required on local streets. On collector and arterial streets, bicycle lanes are as required by the Bicycle Route Master Plan or Public Works Director.

2)

Where bicycle lanes are required, they shall generally be located on both sides of the street. Minimum bicycle lane width within a roadway is four feet, and does not include gutter.

3)

On rural collector streets and urban or rural arterial streets, one off-street bicycle path of ten feet width may be provided to satisfy the bicycle lane requirement. Off-street bicycle paths are preferable along primary arterials.

G)

Sidewalks.

1)

Sidewalks shall generally be placed on both sides of a street. Minimum sidewalk width is five feet exclusive of the abutting curb width.

2)

Sidewalks are not required on rural local residential streets. For rural street types, sidewalks or all-weather paths may be installed alongside roads to the outside of drainage swales, or independent of roads to improve connectivity.

3)

On local commercial streets, minimum sidewalk width is six feet, except on blocks where the average parcel frontage is 50 feet or less, in which case the minimum sidewalk width is eight feet.

4)

On collector and arterial streets, sidewalks are required for urban street types, including a four-foot verge (landscaping buffer) between the sidewalk and curb. The minimum sidewalk width on urban arterial streets is six feet. For rural collector or arterial streets, sidewalks may be required as specified by the Sidewalk Master Plan, and may be located independent of street location.

5)

Sidewalk widths for specific streets are as follows:

a.

Eight feet on Bullard Street between San Vicente Street and Sixth Street;

b.

Six feet on Bullard Street between Sixth Street and Ninth Street;

c.

Eight feet, nine inches on Broadway Street between Bullard Street and Pinos Altos Street;

d.

Six feet on Broadway Street between Pinos Altos Street and Cooper Street.

e.

Sidewalks not less than six feet wide may be required by Town staff or the Planning and Zoning Commission to provide circulation in high pedestrian traffic areas, such as schools, playgrounds, churches, shopping centers, transportation, and other community facilities.

6)

Sidewalks may be located on only one side of a street where there is insufficient right-of-way or topographic constraints, subject to approval by the Planning and Zoning Commission. When allowed only on one side, sidewalks should be located on the north and east sides of the street to facilitate snowmelt.

7)

Additional sidewalk design standards are listed in Section 5.4.

H)

Cul-de-sac Lengths, Block Lengths, and Connectivity.

1)

Culs-de-sac, designed to be so permanently, shall be provided at the closed end of a street with a turnaround having a right-of-way radius of at least 50 feet, and shall be no more than 400 feet long on urban streets. Cul-de-sac lengths for rural streets shall be no longer than 2,500 feet or the length needed to access 30 dwelling units, whichever is less.

2)

Block lengths within subdivisions are given in Section 5.1.5(A).

3)

Where necessary to give access to, or permit satisfactory future division of adjoining land, streets shall be extended to the boundary of the subdivision, or partition, and the resulting dead-end streets ("street stubs") may be approved without a turnaround.

4)

The Town may require additional street connections to reduce congestion at access points and to ensure adequate emergency access.

I)

Street Grades.

1)

Minimum street grade is 0.3 percent as an average over 300 feet.

2)

Maximum street grades are set forth in Table 5.2. On local residential streets, grade may be increased to 14 percent over a distance less than 300 feet. On collector streets, grade may be increased to 12 percent over a distance less than 500 feet.

J)

Minimum Street Widths. All streets shall have allowance for a 16-foot emergency lane.

5.2.4 Streets and alleys laid out in any development within the Town shall be continuous with and correspond in direction and width to the streets and alleys of the Town's Comprehensive Plan. Where such streets and alleys are not shown in the Comprehensive Plan, the arrangement of streets and alleys shall either:

A)

Provide for the continuation or appropriate projection of existing principal streets in surrounding areas, or

B)

Conform to a plan for the neighborhood approved or adopted by the Town's Planning and Zoning Commission to meet a particular situation where topographic or other conditions make continuance or conformance to existing streets impractical.

5.2.5 Where a development abuts or contains an existing or proposed arterial street, the Town may require marginal access streets, reverse frontage with screen planting or walls contained in a non-access reservation along the rear property line, deep lots with rear service alleys, or such special treatment as may be necessary for adequate protection of residential properties to afford separation of through and local traffic. The Public Works Director may require consistency with existing streets or consistency with the minimum width requirements, whichever is greater.

5.2.6 Where a subdivision borders on or contains a railroad right-of-way, highway, or a natural physical barrier such as an arroyo, the Town may require a street approximately parallel to and on each side of the right-of way, at a distance suitable for the appropriate use of the intervening land, as for park or recreational purposes in residential zones or districts, or for commercial or industrial purposes in appropriate zones or districts. These distances also shall be determined with due regard for the requirements of approach grades and future grade separations.

5.2.7 Every subdivision and subdivided lot shall be served from a publicly dedicated street. There shall be no private streets platted in any subdivision where lots will be held under separate ownership, unless expressly provided for in this Land Use Code.

5.2.8 Street jogs with center line offsets of less than 125 feet shall not be allowed.

5.2.9 A tangent of at least 50 feet long shall be introduced between reverse curves on arterial and collector streets.

5.2.10 When connecting street lines deflect from each other at any one point by more than ten degrees, they shall be connected by a curve with a radius adequate to ensure a sight distance of not less than 200 feet for local and collector streets and for special cases of a greater radius as determined by the Public Works Director.

5.2.11 Streets shall be laid out to intersect as nearly as possible at right angles, and no street shall intersect any other street at an angle of less than 75 degrees. An arterial street intersecting with another street shall have at least 100 feet of tangent adjacent to the intersection. Other streets shall have at least 50 feet of tangent adjacent to the intersection.

5.2.12 Property lines at street intersections shall be rounded with a minimum radius of 25 feet. The Planning and Zoning Commission may permit comparable cutoffs or chords in place of rounded corners.

5.2.13 Half streets shall be prohibited. Whenever a half-width street exists adjacent to a tract to be subdivided, the other half of the street shall be platted within the tract to be subdivided.

5.2.14 No street names shall be used which will duplicate or be confused with the names of existing streets. Use of suffixes such as "street," "avenue," "place," "court," or similar description shall not be a distinction sufficient to meet this requirement.

5.2.15 If the tract of land proposed to be subdivided or any part thereof lies adjacent to a highway over which the New Mexico State Highway and Transportation Department has jurisdiction with respect to maintenance and upkeep thereof, and an entrance or entrances are desired from such highway to lots, streets, roadways or alleys in such proposed subdivision, the subdivider shall submit to the Town a written document from the New Mexico State Highway and Transportation Department giving him or her tentative permission to obtain and construct such entrance or entrances.

5.2.16 All public streets within the corporate limits of the Town shall be improved in accordance with the following guidelines:

A)

Streets shall be surfaced with a minimum of two inches of asphaltic pavement on a crushed aggregate base of not less than seven inches in thickness and of plasticity index no greater than 12. Base thickness may be reduced with a stabilized base of equivalent strength. Subgrade and crushed aggregate base shall be compacted to withstand a loaded ten yard truck with no appreciable deflection.

B)

Curbs and gutters on collector and local streets where required shall not be less than 24 inches in overall width and not less than seven inches thick where gutter abuts the street pavement. A combined curb and gutter. built with a slope of one vertical inch to one horizontal foot shall be used on streets designed to carry the major portion of the runoff of a subdivision or a tapered curb and gutter with crowned or inverted streets 24 inches in width, seven inches thick at pavement, 12 inches thick at curb. Concrete shall develop a minimum comprehensive strength of 3,000 pounds per square inch (psi) in 28 days as determined by test cylinders made and tested in accordance with American Association of State Highway and Transportation Officials (AASHTO). Minimum cement content shall be 5.5 sacks per cubic yard. Slump shall not be more than four inches and air entrainment shall be five percent, plus or minus one. Failure of two out of three cylinders for any pour shall require the removal of the concrete.

C)

Streets without curb and gutter shall have adequate drainage facilities to carry runoff from road surfaces and adjacent slopes, in accordance with requirements of the Town's Drainage Policy Guide. Shoulders shall be surfaced with a minimum of four inches of stabilized base course or other approved material.

5.2.17 For subdivisions outside of the corporate limits of Silver City but within the ETJ defined and authorized by New Mexico Statute, NMSA 1978, § 3-20-5, all public streets shall be constructed to the standards specified in preceding paragraphs (5.2.1 through 5.2.16) and this Land Use Code.

5.2.18 Speed Humps. Any "speed humps" constructed upon the streets or roadways located within the Town or within the Town's extraterritorial planning and platting jurisdiction and subject to the developmental standards of this Land Use Code shall be placed, constructed, and maintained according to the standards and specifications of the Town of Silver City Municipal Code.