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.

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.

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 19P

See similar textbooks

Similar questions

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 = 0.15
Two straight sections of road are to be linked by a wholly transitional curve comprising two clothoid spiral curves with differing rates of gain of radial acceleration. Deflection angle between the two straight sections of road 43.5 Design Speed 75 Rate of gain of radial acceleration for entry transition curve 0.400 Rate of gain of radial acceleration for exit transition curve 0.600 Answers required: a) What is the value of the point radius where the two transition curves meet?
A section of highway has vertical and horizontal curves with the same design speed. A vertical sag 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 12ft lanes, has a central angle of 37 degrees, and has a superelevation of 6%, what is the length of the horizontal curve?
What is the appropriate super elevation rate for a curve with a 1,200-ft radius on highway with a design speed of 60 mi/h? The maximum design super elevation is 6% for this highway.
Traffic Engineering vertical curve problem. Solve the d,e,f part
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
Engineers group have been decided to design a highway with vertical curve in order to transfer the traffic volume through it, with a (1.90) percent grade meting (- 3.90) percent grade. The vertical curve length (984.00) ft. (Use fSkidding= 0.35, t = 2.5 sec.), sight distance you :recommended is 677 ft. 505 m. O 605 ft. O 650 ft. O 600 ft. O
Highway Engineering: You are designing a highway to AASHTO guidelines on rolling terrain where the design speed will be 65 mi/h. At one section, a +1.25% grade and a -2.25% grade must be connected with an equal-tangent vertical curve. Determine the SSD given the reaction time of 2.5 sec and deceleration of 3.4 m/s^2. Determine also the minimum length of curve.
The 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. 1
2 Vertical curves A crest vertical curve is to be designed to join a 2.5% upgrade with a 3% downgrade at a section of a two-lane highway. The design speed of the highway is 55 mi/h. A. Determine the minimum length of the curve for safe stopping sight distance (demonstrate that the used formula for L satisfies the appropriate relation between L and SSD). Use design values for the PIEV time and vehicle deceleration rate once the brakes are hit. B. If the elevation of PVI point is 400 ft above the sea-level, calculate the elevation of PVC point above the sea level (Y). C. Write down the parabolic equation of the vertical curve denoting its height (Y) as a function of horizontal distance from the PVC point (x). I
PROBLEM #1) An existing highway with bearing of N 20deg E to be connected to another highway, with bearing of N 75deg E, by a 4-degree simple curve. What length of curve is required? (SIMPLE AND COMPOUND CURVES) Can you answer this too using the same formula?
Q 1: Determine the minimum length of a highway sag curve (based on SSD Criterion) that is designed to join a - 0.035 grade to a + O.025 grade, if the design speed is 90 km/h. Assume a = 3.4 m/s2, t = 2.5 s.