CE 480: Transportation Engineering Homework #8 Due: October 26, 2017 (80 points)
ID: 1712889 • Letter: C
Question
CE 480: Transportation Engineering Homework #8 Due: October 26, 2017 (80 points) I. (5 pts) A driver traveling at 65 mph rounds a curve on a l% downgrade and sees overturned across the roadway at a distance 550 ft. If the driver is able to decelerate at a rate of 11.2 f/sec, will the vehicle hit the truck? truck (40 pts) A vertical curve with length of 650 feet is designed to connect a grade of 4% to grade of-290. The VPI is located at station 552+21 and has a known elevation of 547 feet The design speed is 60 mph. Find the following: 2 a The station and elevation of the VPC and VPT a. b. The elevations of points along the vertical curve at 100-ft stations c. d. The location (distance and station) and elevation of the high point on the curve Does the existing curve length satisfy SSD requirements? PSD requirements? 3 (35 pts) A vertical curve is to be designed to connect a .7% grade to a 21% grade on a rural two lane highway with a design speed of 60 mph. For economic reasons, a minimum length curve to satisfy SSD requirements will be provided. The VPI of the curve is at station 423+22 and has an elevation of 489 feet. Find the following a. The station and elevation of the VPC and VPT b. The elevations of points along the vertical curve at 100-ft stations c. The location (distance and station) and elevation of the low point on the curveExplanation / Answer
1.
Given:
Time taken for the vehicle to come to rest i.e. final velocity (v) = 0:
With a constant deceleration of 11.2 ft/sec2, the vehicle will come to rest in a distance of only 405.7 feet, so the vehicle will not hit the truck which is 550 feet away.