Street Class
|
Right-of-way
(feet)
|
Maximum Average Daily Traffic Volume
|
---|---|---|
Collectors, major
|
80
|
Above 8,000
|
Collectors, minor
|
60
|
800 to 8,000
|
Locals
|
50
|
Less than 800
|
Alleys
|
Not permitted
|
Collector, Major
(feet)
|
Collector, Minor
(feet)
|
Local
(feet)
| |
---|---|---|---|
Minimum center-line radius
|
600
|
500
|
300
|
Minimum tangent between reverse curves
|
200
|
160
|
120
|
Intersection radius (curb returns)
|
40
|
30
|
25
|
Minimum intersection radius shall be determined
by highest street class in intersection; right-of-way line shall be
concentric thereto
|
Street Class
|
Crest Curve
(feet)
|
Sag Curve
(feet)
|
---|---|---|
Collector, major
|
145
|
100
|
Collector, minor
|
65
|
60
|
Local
|
28
|
35
|
Intersections (stop conditions)
|
3
|
3
|
Residential
|
Minimum
(feet)
|
Maximum
(feet)
|
---|---|---|
Single driveway
|
8
|
20
|
Double driveway
|
16
|
20
|
Other uses
|
25
|
40
|
Street Class
|
Minimum Average Maintained Footcandles
|
Uniformity
(average to minimum)
|
---|---|---|
Collectors, major
|
0.5
|
6:1
|
Collectors, minor
|
0.3
|
—
|
Local
|
0.2
|
—
|
Topography
| |||||
---|---|---|---|---|---|
Usage
|
Density
(Units/Acre)
|
Flat
0%-10%
|
Rolling
10%-20%
|
Hilly
Over 20%
| |
Residential
| |||||
High density
|
4-6
|
0.50(0.40)
|
0.55(0.45)
|
0.60(0.55)
| |
Medium density
|
1-4
|
0.45(0.35)
|
0.50(0.40)
|
0.55(0.55)
| |
Low density
|
Less than 1
|
0.40(0.30)
|
0.45(0.35)
|
0.50(0.45)
| |
Impervious surfaces
| |||||
Undeveloped woodland
|
0.30(0.20)
|
0.35(0.25)
|
0.50(0.45)
| ||
Pasture and grassed areas
|
0.30(0.20)
|
0.36(0.20)
|
0.42(0.37)
| ||
Cultivated fields
|
0.50(0.50)
|
0.60(0.50)
|
0.72(0.62)
|
The above runoff coefficients assume
that clay soils (sand, gravel soils coefficients indicated in parenthesis)
are present and that paved areas (parking) have been provided. Any
deviation from these factors would result in an adjustment in "C"
values. Determination of nonlisted uses shall be subject to special
study and approved by the Township Engineer.
|
V equals 1.486 x R 2/3 x S 1/2
n
|
Concrete pipe
|
0.012
|
Corrugated metal
|
2 2/3 x 1/2 corrugations
|
Plain or fully coated
|
0.024
|
Paved invert
|
0.020
|
Fully paved
|
0.012
|
3" x 1" corrugation
|
0.027
|
6" x 2" corrugation (field bolted)
|
0.032
|
Desirable Minimum Gradients for Concrete
Pipe
| |
---|---|
Diameter
(inches)
|
Slope
N equals 0.012
|
15
(minimum permissible)
|
.008
|
18
|
.006
|
24
|
.005
|
30
|
.004
|
36
|
.003
|
42
|
.002
|
48
|
.0016
|
54
|
.0014
|
60
|
.0012
|
66
|
.0011
|
Unlined
| ||
Earth uniform section
|
0.018-0.027
| |
Earth nonuniform section
|
0.025-0.040
| |
Earth not maintained
|
0.080-0.012
| |
Lined-concrete
| ||
Finished
|
0.015
| |
Rough
|
0.25
| |
Riprap
|
0.35
|
Materials
|
Velocity
|
---|---|
Fine sand to fine loam
|
2.5 to 3.5 fps
|
Stiff clay to hardpan
|
3.75 to 6.00 fps
|
Concrete-lined ditch
|
15 fps
|
Velocities shall be controlled by use of check
dams or baffles where necessary
|
Facility
|
Maximum Side Slope
|
---|---|
Channel
|
2:1
|
Ditch
|
4:1
|
Swale
|
6:1
|