The fundamental approach to street design presented herein is to first identify the design speed the facility is to accommodate and the nominal vehicle type which is to govern the design. Designing is then accomplished by selection of appropriate characteristics to accommodate the design vehicle at the design speed in a safe and efficient manner at reasonable cost on a durable street. Table 7-A, "Summary Of Road Design Elements", of this section summarizes criteria considered minimum in village of Angel Fire for various classifications of streets. Design speeds given are intended to establish levels to which facilities are to be designed; posted legal speeds are established only after appropriate examination of the completed street by the village public works director.
TABLE 7-A
SUMMARY OF ROAD DESIGN ELEMENTS
Design Element | Arterial1 | Collector | Local Access | Local Volume | Primitive |
Right of way (minimum) | 100 | 80 | 60 | 50 | 40 |
Recommended design speed | 40–55 | 35–45 | 25–35 | 20–35 | 20–30 |
Design capacity (ADT) | 2,000– 4,999 | 601– 1,999 | 301–600 | 500 | 100 |
Number of lanes | 2–4 | 2 | 2 | 2 | 1–2 |
Lane width | 12' | 12' | 12' | 12' | 10'–12'2 |
Shoulders | 6' | 4' | 2' | 2' | 0' |
Maximum sustained grade | 8% | 8%3 | 8%3 | 10% | 12% |
Surfacing requirements (minimum) | 4" PMBP4 | 3" PMBP4 | 2" PMBP4 | Double penetration chip seal4 | 4" aggregate base |
Aggregate base course (minimum) | 12"4 | 8"4 | 6"4 | 6"4 | 4" |
Crown slope | 2% | 2% | 2% | 2% | 3%5 |
Ditch section cut slope: | |||||
Foreslope/backslope (maximum) | 4:1/2:16 | 4:1/2:16 | 3:1/2:16 | 3:1/2:16 | 2:1/1.5:16 |
Ditch section fill slope: | |||||
Foreslope/backslope (maximum) | 4:1/2:16 | 4:1/2:16 | 3:1/2:16 | 3:1/2:16 | 2:1/1.5:16 |
Notes:
1. Applies to minor arterial only. Principal arterial design elements must conform to those established by the NMDOT and/or the FHWA.
2. For roads having 1 lane, lane must be 12 feet; for roads having 2 lanes, each lane must be 10 feet.
3. See guidelines for exceptions.
4. The greater of the minimum requirements in this table or the requirements identified in a pavement structural design shall be used.
5. 3 percent crown slope required for all roads with an aggregate base gravel finished surface.
6. Slopes must be properly protected to prevent erosion.
(Ord. 2007-06, 8-14-2007)