§ 94.015 SIDEWALK DESIGN.

   (A)   Sidewalks. (See Standard Details -- See Appendix A to Ord. No. 2006-02). Sidewalks must be provided for all subdivided properties resulting in over 25 lots within the county. The fundamental requirements governing sidewalk design are established by these design standards. Sidewalk designs must provide for the mobility, safety, and comfort of the pedestrian and provide for adequate pedestrian access to abutting property. Pertinent sidewalk design criteria are collected herein for the convenience of the designer.

      (1)   Sidewalk width shall be 4-feet 0-inch minimum. For roads or streets in commercial or industrial zones, the county may require wider sidewalks based on expected pedestrian traffic.

      (2)   Sidewalk location- horizontal.

         (a)   Along collector and local roads or streets, sidewalks must be located within the right-of-way with the property side edge of the walk at the property line.

         (b)   Variances from sidewalk standards will require the approval of the county.

      (3)   Traverse slope. Sidewalks must be provided with a transverse slope of 1/4 to 1/2 inch per foot, sloping toward the road or street.

      (4)   Sidewalk location – vertical. The sidewalk must be located vertically such that the top surface of the sidewalk will be at or above the top of curb at the lowest point on the sidewalk, and must be appropriate to the overall street section design within the right-of-way.

      (5)   Sidewalk materials. Sidewalks are to be of Portland cement, Class “A”, 4,000 psi, of minimum 4 inches thickness. Portland cement concrete reinforcing, curing compound shall be as specified in the New Mexico Standard Specifications for Public Works Construction. The county must approve designs incorporating alternate materials. Expansion joints shall be a minimum of every 12 feet and construction joints every 4 feet. Sidewalk and curb and gutter joints shall match each other.

TABLE 2. GENERAL DESIGN CRITERIA FOR ROADS OR STREETS

Street Classification	Minimum Centerline Radius - Feet (5)			Minimum Length Vertical Curve (feet) (1)	Vertical Curvature Design Value K (2)			Maximum Grade Change Allowed Without Vertical Curve - % (8)	Maximum Grade Allowed % (11)
	Design Speed M.P.H	With 0.02 ft./ft (10) Super- elevation	With Normal Crown (7)		For Crest Stopping Sight Distance (6)	For Sag Stopping Sight Distance (6)	For Sag Comfort Control (3) (6)
Principal Arterial	50	1,050	1,400	150	100	75	N/A	0.4	6
Minor Arterial	45	800	1,100	135	80	65	N/A	0.4	7
Collector	35	450	575	100	46	45	26	0.7	8
Local Residential	25	0	230 (9)	75	25	28	13	1	8
Cul-de-sacs & Alleys	20	0	120 (9)	60	18	24	9	1	12
Local Industrial/ Commercial	30	300	380	90	32	35	19	1	8

 

 

(1)   Controlling limit only when algebraic grade difference (A) times the design value K is less than minimum shown; in all other cases, L=KA shall control. (2)   The values for K shown are to be used in determining the minimum length of vertical curve required by the use of the relationship L=KA where: L= Length of vertical curve in feet A= Algebraic difference in grades expressed in percent K= Design value indicative of rate of curvature (3)   Allowed only with express permission of county. Use of K for comfort is strongly discouraged. (4)   Lengths of vertical curves longer than the minimums resulting from the use of K values shown should be used wherever possible; however, K should not exceed 143 feet when curb and gutter is used. (5)   Source: Design of Urban Roads or Streets, Federal Highway Administration, U.S. Department of Transportation (6)   Crest vertical curves are based on eye height of 3 feet 3 inches, object height of 0 feet, 6 inches and AASHTO minimum stopping distances. SAG vertical curves are based on AASHTO standards. If AASHTO standards are revised to more restrictive values, the more restrictive values shall supersede the values in this table. (7)   As given in Standard Details. (8)   A minimum of 50 feet must be maintained between vertical points of intersection. (9)   Local residential roads or street with 90-degree or near 90-degree turns may be designed with a minimum centerline radius of 75 feet with the approval of the county. Appropriate advisory signs may be required. (10)   0.04 ft./ft/ allowed for principal arterials only. (11)   Notwithstanding these permissible grades, all designs shall be compliant with the Americans with Disabilities Act..

 

(Ord. 2006-02, passed 3-17-2006)