Traffic and Highway Engineering
5th Edition
ISBN: 9781305156241
Author: Garber, Nicholas J.
Publisher: Cengage Learning
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Question
Chapter 5, Problem 20P
To determine
The crash modification factor for a horizontal curve on a two-lane rural highway.
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A curve of radius 76 m and e = 0.08 is located at a section of an existing rural highway, which restricts the safe speed at this section of the highway to 50% of the design speed. This drastic reduction of safe speed resulted in a high crash rate at this section. To reduce the crash rate, a new alignment is to be designed with a horizontal curve. Determine the minimum radius of this curve if the safe speed should be increased to the design speed of the highway. Assume fs = 0.17 for the existing curve. The new curve is to be designed with the same superelevation
Problem 5
An existing horizontal curve on a highway has a radius of 465 ft, which restricts the posted speed limit to
only 61.5% of the design speed on this section of the highway. If the curve is to be improved, so that its
posted speed will be the design speed of the highway, determine the minimum radius of the new curve.
Assume that the rate of superelevation is 0.08 for both the existing curve and the new curve to be
designed and f,=0.16 for 40 mph, 0.14 for 50 mph, 0.12 for 60 mph, and 0.10 for 70 mph.
A curve of radius 250 ft and e 0.08 is located at a section of an existing rural highway, which restricts the safe speed at this section of the highway to 50% of the design speed. This drastic reduction of safe speed resulted in a high crash rate at this section. To reduce the crash rate, a new alignment is to be designed with a horizontal curve. Determine the minimum radius of this curve if the safe speed should be increased to the design speed of the highway. Assume fs= 0.17 for the existing curve, and the new curve is to be designed with e = 0.08
Chapter 5 Solutions
Traffic and Highway Engineering
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