An equal-tangent vertical curve was designed in 2000 for a design speed of 70 mi/h to connect grades G1 = +1% and G2 = -2%. The curve is to be redesigned for a 70-mi/h design speed in the year 2020. Vehicle braking technology has advanced so that the recommended design deceleration rate is 25% greater than the 2000, but due to the higher percentage of older persons in the driving population, design reaction times have increased by 20%. Compute the difference in design curve lengths for the 2000 and 2020 designs.

An equal-tangent vertical curve was designed in 2000 for a design speed of 70 mi/h to connect grades G1 = +1% and G2 = -2%. The curve is to be redesigned for a 70-mi/h design speed in the year 2020. Vehicle braking technology has advanced so that the recommended design deceleration rate is 25% greater than the 2000, but due to the higher percentage of older persons in the driving population, design reaction times have increased by 20%. Compute the difference in design curve lengths for the 2000 and 2020 designs.

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter15: Geometric Design Of Highway Facilities

Section: Chapter Questions

Problem 8P

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