Design Guidelines
Street Class | Right-of-Way (feet) | Maximum Average Daily Traffic Volume | Width (feet) |
|---|---|---|---|
Major collector | 60 | Above 8,000 | 40 |
Minor collector | 60 | 800 to 8,000 | 36 |
Local | 50 | Less than 800 | 30 |
Alley | Not permitted |
Street Class | |||
|---|---|---|---|
Design Standard | Major Collector (feet) | Minor Collector (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 the highest street class in the intersection, and the right-of-way line shall be concentric thereto. |
L= KA | |
|---|---|
The minimum K values shall be as follows: |
Street Class | Crest Curve | Sag Curve |
|---|---|---|
Major collector | 145 | 100 |
Minor collector | 65 | 60 |
Local | 28 | 35 |
Intersection (stop condition) | 3 | 3 |
Street Class | Sight Distances (feet) |
|---|---|
Major collector | 350 |
Minor collector | 275 |
Local | 200 |
Width | |||
|---|---|---|---|
Use | Minimum (feet) | Maximum (feet) | |
Residential | |||
Single driveway | 8 | 20 | |
Double driveway | 16 | 20 | |
Other uses | 25 | 40 | |
Street Class | Minimum Average Maintained Footcandles | Uniformity (average to minimum) |
|---|---|---|
Major collector | 0.5 | 6:1 |
Minor collector | 0.3 | — |
Local | 0.2 | — |
Q = CIA | |
|---|---|
Where: |
Topography | |||||
|---|---|---|---|---|---|
Usage | Density (units per acre) | Flat (0% to 10%) | Rolling (10% to 20%) | Hilly (over 20%) | |
Residential: | |||||
High density | 4 to 6 | 0.50(0.40) | 0.55(0.45) | 0.60(0.55) | |
Medium density | 1 to 4 | 0.45(0.35) | 0.50(0.40) | 0.55(0.50) | |
Low density | Less than 1 | 0.40(0.30) | 0.45(0.35) | 0.50(0.45) | |
Impervious surfaces | — | 0.90 | 0.90 | 0.90 | |
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, and any deviation from these factors would result in an adjustment in C values. Determination of nonlisted uses shall be a subject of special study and approved by the Township Engineer. |
The minimum time of concentration shall be 10 minutes. |
Type of Material | n Value | |
|---|---|---|
Concrete pipe | 0.012 | |
Corrugated metal, two-and-two-thirds-inches-by-one-half-inch corrugations | ||
Plain or fully coated | 0.024 | |
Paved invert | 0.020 | |
Fully paved | 0.012 | |
Three-inches-by-one-inch corrugation | 0.027 | |
Six-inches-by-two-inches corrugation (field bolted) | 0.032 | |
Desirable Minimum Gradients for Concrete Pipe | |
|---|---|
Diameter (inches) | Slope n = 0.012 |
15 (minimum permissible) | 0.008 |
18 | 0.006 |
24 | 0.005 |
30 | 0.004 |
36 | 0.003 |
42 | 0.002 |
48 | 0.0016 |
54 | 0.0014 |
60 | 0.0012 |
66 | 0.0011 |
Unlined | Friction Factor | |
Earth, uniform section | 0.018 to 0.027 | |
Earth, nonuniform section | 0.025 to 0.040 | |
Earth not maintained | 0.080 to 0.012 | |
Lined | Friction Factor | |
Concrete | ||
Finished | 0.015 | |
Rough | 0.25 | |
Riprap | 0.35 | |
Materials | Velocity (feet per second) |
|---|---|
Fine sand to fine loam | 2.5 to 3.5 |
Stiff clay to hardpan | 3.75 to 6.00 |
Concrete-lined ditch | 15 |
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 |
Street Class | Minimum Sight Distance (feet) |
|---|---|
Local | 200 |
Minor collector | 275 |
Major collector | 350 |
Other | 400 |
Area | Average Maintained Footcandles | |
|---|---|---|
Parking lots | ||
Shopping centers | 1.5 to 5 | |
Retail businesses | 1.0 to 4.0 | |
Industrial | 0.5 to 1.0 | |
Residential, multifamily | 0.4 to 1.0 | |
Access driveways | ||
Shopping centers | 2.0 to 3.0 | |
Retail businesses | 1.0 to 3.0 | |
Industrial | 1.0 to 3.0 | |
Park areas and pedestrianways | 0.4 | |
Sidewalks | 0.5 | |
Intersections | 2.0 to 5 | |
Other areas | As determined by individual study | |
Design Guidelines
Street Class | Right-of-Way (feet) | Maximum Average Daily Traffic Volume | Width (feet) |
|---|---|---|---|
Major collector | 60 | Above 8,000 | 40 |
Minor collector | 60 | 800 to 8,000 | 36 |
Local | 50 | Less than 800 | 30 |
Alley | Not permitted |
Street Class | |||
|---|---|---|---|
Design Standard | Major Collector (feet) | Minor Collector (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 the highest street class in the intersection, and the right-of-way line shall be concentric thereto. |
L= KA | |
|---|---|
The minimum K values shall be as follows: |
Street Class | Crest Curve | Sag Curve |
|---|---|---|
Major collector | 145 | 100 |
Minor collector | 65 | 60 |
Local | 28 | 35 |
Intersection (stop condition) | 3 | 3 |
Street Class | Sight Distances (feet) |
|---|---|
Major collector | 350 |
Minor collector | 275 |
Local | 200 |
Width | |||
|---|---|---|---|
Use | Minimum (feet) | Maximum (feet) | |
Residential | |||
Single driveway | 8 | 20 | |
Double driveway | 16 | 20 | |
Other uses | 25 | 40 | |
Street Class | Minimum Average Maintained Footcandles | Uniformity (average to minimum) |
|---|---|---|
Major collector | 0.5 | 6:1 |
Minor collector | 0.3 | — |
Local | 0.2 | — |
Q = CIA | |
|---|---|
Where: |
Topography | |||||
|---|---|---|---|---|---|
Usage | Density (units per acre) | Flat (0% to 10%) | Rolling (10% to 20%) | Hilly (over 20%) | |
Residential: | |||||
High density | 4 to 6 | 0.50(0.40) | 0.55(0.45) | 0.60(0.55) | |
Medium density | 1 to 4 | 0.45(0.35) | 0.50(0.40) | 0.55(0.50) | |
Low density | Less than 1 | 0.40(0.30) | 0.45(0.35) | 0.50(0.45) | |
Impervious surfaces | — | 0.90 | 0.90 | 0.90 | |
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, and any deviation from these factors would result in an adjustment in C values. Determination of nonlisted uses shall be a subject of special study and approved by the Township Engineer. |
The minimum time of concentration shall be 10 minutes. |
Type of Material | n Value | |
|---|---|---|
Concrete pipe | 0.012 | |
Corrugated metal, two-and-two-thirds-inches-by-one-half-inch corrugations | ||
Plain or fully coated | 0.024 | |
Paved invert | 0.020 | |
Fully paved | 0.012 | |
Three-inches-by-one-inch corrugation | 0.027 | |
Six-inches-by-two-inches corrugation (field bolted) | 0.032 | |
Desirable Minimum Gradients for Concrete Pipe | |
|---|---|
Diameter (inches) | Slope n = 0.012 |
15 (minimum permissible) | 0.008 |
18 | 0.006 |
24 | 0.005 |
30 | 0.004 |
36 | 0.003 |
42 | 0.002 |
48 | 0.0016 |
54 | 0.0014 |
60 | 0.0012 |
66 | 0.0011 |
Unlined | Friction Factor | |
Earth, uniform section | 0.018 to 0.027 | |
Earth, nonuniform section | 0.025 to 0.040 | |
Earth not maintained | 0.080 to 0.012 | |
Lined | Friction Factor | |
Concrete | ||
Finished | 0.015 | |
Rough | 0.25 | |
Riprap | 0.35 | |
Materials | Velocity (feet per second) |
|---|---|
Fine sand to fine loam | 2.5 to 3.5 |
Stiff clay to hardpan | 3.75 to 6.00 |
Concrete-lined ditch | 15 |
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 |
Street Class | Minimum Sight Distance (feet) |
|---|---|
Local | 200 |
Minor collector | 275 |
Major collector | 350 |
Other | 400 |
Area | Average Maintained Footcandles | |
|---|---|---|
Parking lots | ||
Shopping centers | 1.5 to 5 | |
Retail businesses | 1.0 to 4.0 | |
Industrial | 0.5 to 1.0 | |
Residential, multifamily | 0.4 to 1.0 | |
Access driveways | ||
Shopping centers | 2.0 to 3.0 | |
Retail businesses | 1.0 to 3.0 | |
Industrial | 1.0 to 3.0 | |
Park areas and pedestrianways | 0.4 | |
Sidewalks | 0.5 | |
Intersections | 2.0 to 5 | |
Other areas | As determined by individual study | |