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Tools

(Supported by NJDOT Standards and Guidance Documents)


Roadway Design Tool

Design Control For Radius of Horizontal Curve
with Sight Obstruction


U.S. Customary English Units

See Roadway Design Manual Figure 4-A

This program calculates the Radius of a Horizontal Curve, using the measured Horizontal Sightline Offset (HSO) and required Stopping Sight Distance (S).

R = ((HSO)2+(S/2)2)/2HSO

Enter HSO and S


HSO = Horizontal Sightline Offset (ft.)

S = See Table Below (ft.)


 

R = Radius (ft.) to the center line of the inside lane

Design Speed S = Sight Distance
Mph Stopping Distance Minimum
25 155
30 200
35 250
40 305
45 360
50 425
55 495
60 570
65 645
70 730

 

 
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  Department of Transportation
  P.O. Box 600
  Trenton, NJ 08625-0600
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  Last Updated:  February 2, 2011