Design Speed
(miles per hour)
|
Minimum Radius of Horizontal Curves
(feet)
|
Maximum Percent of Grade
|
Minimum Forward Sight Distance
(feet)
|
Minimum Length of Vertical Curve for Each 1% of Change
in Grade
(feet)
| |
---|---|---|---|---|---|
20
|
100
|
10
|
150
|
10
| |
25
|
200
|
10
|
175
|
15
| |
30
|
250
|
10
|
200
|
20
| |
35
|
350
|
10
|
250
|
30
| |
40
|
450
|
8
|
275
|
35
| |
45
|
600
|
8
|
325
|
55
| |
50
|
750
|
8
|
350
|
70
|
Local Roads
| ||||||
---|---|---|---|---|---|---|
Collector Secondary
|
Minor
|
Marginal Access
|
Cul-de-sac
|
Alley
| ||
Minimum right-of-way width (feet)
|
60
|
50
|
50
|
50 (Turnaround radius: 65 feet)
|
20
| |
Minimum pavement width (feet)
|
36
|
28
|
28
|
28
|
18
| |
Maximum grade (percent)
|
8
|
10
|
10
|
10
|
10
| |
Minimum grade (percent)
|
1.0
|
1.02
|
1.02
|
1.02
|
12
| |
Minimum curb radii (feet)
|
20
|
20
|
20
|
20
| ||
Minimum tangent length between reverse curves (feet)
|
200
|
1
|
1
|
1
|
1
| |
Maximum grades within 150 feet of center-line intersections
(percent)
|
1.5
|
1.5
|
1.5
|
1.5
|
1.5
| |
Minimum distance between center-line offsets at street jogs
(feet)
|
150
|
150
|
150
|
150
|
No standards
| |
Maximum length of cul-de-sac3 (feet)
|
800
| |||||
Minimum outside radius of cul-de-sac pavement (feet)
|
45
| |||||
Angle at intersections of street center lines (degrees)
|
90
|
90
|
90
|
90
|
1
|
One hundred feet except where excessive grades may be reduced
to reasonable grades by shortening tangent.
| |
2
|
Grades under 1.0% acceptable when approved stormwater drainage
facilities are provided.
| |
3
|
Except where, in the judgment of the Planning Board, the cul-de-sac
does not impose any problem and constitutes a positive design feature.
| |
Note: Standards are not shown for arterial streets, as they
would in all probability be built by the state or county.
|