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
|
Collector
|
Residential Access
|
Residential Road
|
Private Cul-de-Sac
| ||
---|---|---|---|---|---|
Right-of-way width (feet)
|
50*
|
50*
|
50*
|
50*
Turnaround radius: 30 feet
| |
Pavement width (feet)
(minimum-maximum)
|
18 to 22
|
16 to 18
|
12 to 16
|
12 to 16
| |
Shoulder width (feet)
(minimum-maximum)
|
3 to 6 on 2 sides
|
1 to 2 on 2 sides
|
1 to 2 on 2 sides
|
1 to 2 on 2 sides
| |
Grade (percent)
(minimum-maximum)
|
1 to 10
|
1 to 10
|
1 to 10
|
1 to 10
| |
Curb radii (feet)
(minimum-maximum)
|
5 to 10
|
5 to 10
|
5 to 10
|
5 to 10
| |
Minimum tangent length between reverse curves (feet)
|
100
|
100
|
50
|
50
| |
Maximum grades within 150 feet of center-line intersections
(percent)
|
1.5
|
1.5
|
1.5
|
1.5
| |
Minimum distance between center-line offsets at street jogs
(feet)
|
300
|
125
|
125
|
125
| |
Maximum length of cul-de-sac (feet)
|
800**
| ||||
Minimum outside radius of cul-de-sac pavement (feet)
|
40
| ||||
Angle at intersections of street center lines (degrees)
|
90
|
90
|
90
|
90
|
Notes:
| ||
---|---|---|
*
|
Fifty-foot right-of-way is required by State Highway Law, but
grading and clearing should be reduced to the minimum necessary.
| |
**
|
Except where, in the judgment of the Planning Board, the cul-de-sac
does not impose any problem and constitutes a positive design feature.
| |
Rear lanes, 12 feet to 16 feet in pavement width, are allowed
in hamlet areas and where the size and configuration of the subdivision
are conducive to rear lanes.
| ||
Standards are not given for arterial streets, as they would
in all probability be built by the state or county.
|