Principles of Highway Engineering and Traffic Analysi (NEW!!)
6th Edition
ISBN: 9781119305026
Author: Fred L. Mannering, Scott S. Washburn
Publisher: WILEY
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Question
Chapter 3, Problem 14P
To determine
A satisfactory curve length and check the adequacy of the existing curve in light of the reconstruction design.
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A highway reconstruction project is being undertaken to reduce crash rates. The reconstruction involves a major realignment of the highway such that a design speed of 100km/h attained. At one point on the highway, a 245m equal-tangent crest vertical curve exists. Measurements show that at 0+107.3 stations from the PVC, the vertical curve offset is 1 meter. Assess the adequacy of this existing curve in light of the reconstruction design speed of 100km/h and if the existing curve is inadequate, compute a satisifactory curve length.
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 3 Solutions
Principles of Highway Engineering and Traffic Analysi (NEW!!)
Ch. 3 - Prob. 1PCh. 3 - Prob. 2PCh. 3 - Prob. 3PCh. 3 - Prob. 4PCh. 3 - Prob. 5PCh. 3 - Prob. 6PCh. 3 - Prob. 7PCh. 3 - Prob. 8PCh. 3 - Prob. 9PCh. 3 - Prob. 10P
Ch. 3 - Prob. 11PCh. 3 - Prob. 12PCh. 3 - Prob. 13PCh. 3 - Prob. 14PCh. 3 - Prob. 15PCh. 3 - Prob. 16PCh. 3 - Prob. 17PCh. 3 - Prob. 18PCh. 3 - Prob. 19PCh. 3 - Prob. 20PCh. 3 - Prob. 21PCh. 3 - Prob. 22PCh. 3 - Prob. 23PCh. 3 - Prob. 24PCh. 3 - Prob. 25PCh. 3 - Prob. 26PCh. 3 - Prob. 27PCh. 3 - Prob. 28PCh. 3 - Prob. 29PCh. 3 - Prob. 30PCh. 3 - Prob. 31PCh. 3 - Prob. 32PCh. 3 - Prob. 33PCh. 3 - Prob. 34PCh. 3 - Prob. 35PCh. 3 - Prob. 36PCh. 3 - Prob. 37PCh. 3 - Prob. 38PCh. 3 - Prob. 39PCh. 3 - Prob. 40PCh. 3 - Prob. 41PCh. 3 - Prob. 42PCh. 3 - Prob. 43PCh. 3 - Prob. 44PCh. 3 - Prob. 45PCh. 3 - Prob. 46PCh. 3 - Prob. 47PCh. 3 - Prob. 48PCh. 3 - Prob. 49PCh. 3 - Prob. 50PCh. 3 - Prob. 51PCh. 3 - Prob. 52PCh. 3 - Prob. 53PCh. 3 - Prob. 54PCh. 3 - Prob. 55PCh. 3 - Prob. 56PCh. 3 - Prob. 57PCh. 3 - Prob. 58PCh. 3 - Prob. 59PCh. 3 - Prob. 60PCh. 3 - Prob. 61PCh. 3 - Prob. 62PCh. 3 - Prob. 63PCh. 3 - Prob. 64PCh. 3 - Prob. 65PCh. 3 - Prob. 66PCh. 3 - Prob. 67P
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- The design speed of a highway is 80 km/h. There is a horizontal curve of radius 200 m in a certain locality. What should be the superelevation required to maintain this design speed? If the maximum superelevation of 0-07 is not to be exceeded, what should be the maximum allowable speed on this curve ? Also determine the extra widening required and length of transition curve using the following data: Length of wheel base of the largest vehicle = 6-1 m Pavement width=7-2 m Number of lanes = 2 Rate of introduction of superelevation = 1 in 200 Type of terrain Plain Safe limit of coefficient of friction = 0.15arrow_forwardCalculate the minimum length of a crest vertical curve for a two lane highway with an initial grade of +3.5% and a final grade of -2% based on a Passing Sight Distance (PSD) of 700 ft (i.e. corresponding to a design speed of 45 mph). For Passing Sight Distance, AASHTO 2011 policy assumes a driver eye height above the roadway of 3.5ft (i.e. h1) and an object height of 3.5 ft (i.e. h2). TRANSPORTATION ENGINEERING-IIarrow_forwardA vertical curve was designed in 2005 for SSD requirements at a design speed of 120 km/h to connect grades G1=+2% and G2=-3%. The curve is to be redesigned for the same design speed in 2025. Vehicle braking technology has advanced such that the vehicle deceleration rate has increased by 40% relative to the value used in the original design. However, due to the higher percentage of older people in the driving population, design reaction times have increased by 20%. Compute the difference in design curve lengths for the 2005 and 2025 designs based on Australian guidelines.arrow_forward
- 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.arrow_forwardA section of highway has vertical and horizontal curves with the same design speed. A vertical curve on this highway connects a +1% and a +3% grade and is 420 ft long. If a horizontal curve on this highway is on a two-lane section with 12-ft lanes and has a central angle of 37 degrees and a superelevation of 6%, what is the length of the horizontal curve?arrow_forwardThe radius of a horizontal curve on an existing highway was field- measured to be 275 m. The on this two-lane pavement highway is 6.8 m wide, and the elevation difference between the inside edge and outside edge of the curve is 0.544 m. The posted speed limit on the road is 100 km/h. Determine the minimum radius of curvature to permit safe operation at the speed limit. 1arrow_forward
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