EBK PRINCIPLES OF HIGHWAY ENGINEERING A
6th Edition
ISBN: 9781119299332
Author: WASHBURN
Publisher: JOHN WILEY+SONS,INC.-CONSIGNMENT
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Question
Chapter 2, Problem 25P
To determine
The speed of the car just before it impacts the object.
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A car is traveling up a 2% grade at 70 mi/h on good, wet pavement. The driver brakes to try to avoid hitting stopped traffic that is 250 ft ahead. The driver's reaction time is 0.5 s. At first, when the driver applies the brakes, a software flaw causes the anti-lock braking system to fail (brakes work in non-anti-lock mode with 80% efficiency), leaving 80 ft skid marks. After the 80 ft skid, the anti-lock brakes work with 100% efficiency. How fast will the driver be going when the stopped traffic is hit if the coefficient of rolling resistance is constant at 0.013? (assume minimum theoretical stopping distance and ignore aerodynamic resistance)
A car is driving at 75 mph down a 4.0 % grade on poor, wet pavement. The car's braking efficiency is 90%. The driver
saw an object which is 480 ft away and applied the brake, and his reaction time was 1.0 second. The car's antilock
braking system (ABS) works. Just after seeing the object, which of the following is closest to the distance (in ft)
traveled before applying the brake?
(Assume theoretical stopping distance ignore air resistance and let yb= 1.04 and fr = 0.015).
153 ft
B) 127 ft
135 ft
A car is traveling up a 3% grade, with the speed of 85mph, on a road that has good, wet pavement. A deer jumps out onto the road and the driver applies the brakes 290-ft from it. The driver hits the deer at a speed of 20mph.If the driver did not have antilock brakes, and the wheels were locked the entire distance, would a deer-impact speed of 20mph be possible? (Hint: check the braking efficiency) [Use Theoretical Stopping Distance]
Chapter 2 Solutions
EBK PRINCIPLES OF HIGHWAY ENGINEERING A
Ch. 2 - Prob. 1PCh. 2 - Prob. 2PCh. 2 - Prob. 3PCh. 2 - Prob. 4PCh. 2 - Prob. 5PCh. 2 - Prob. 6PCh. 2 - Prob. 7PCh. 2 - Prob. 8PCh. 2 - Prob. 9PCh. 2 - Prob. 10P
Ch. 2 - Prob. 11PCh. 2 - Prob. 12PCh. 2 - Prob. 13PCh. 2 - Prob. 14PCh. 2 - Prob. 15PCh. 2 - Prob. 16PCh. 2 - Prob. 17PCh. 2 - Prob. 18PCh. 2 - Prob. 19PCh. 2 - Prob. 20PCh. 2 - Prob. 21PCh. 2 - Prob. 22PCh. 2 - Prob. 23PCh. 2 - Prob. 24PCh. 2 - Prob. 25PCh. 2 - Prob. 26PCh. 2 - Prob. 27PCh. 2 - Prob. 28PCh. 2 - Prob. 29PCh. 2 - Prob. 30PCh. 2 - Prob. 31PCh. 2 - Prob. 32PCh. 2 - Prob. 33PCh. 2 - Prob. 34PCh. 2 - Prob. 35PCh. 2 - Prob. 36PCh. 2 - Prob. 37PCh. 2 - Prob. 38PCh. 2 - Prob. 39PCh. 2 - Prob. 40P
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- compute the braking distance for a car moving at an initial velocity of 80 kph and a final velocity of 60 kph. slope of roadway is +6% the coefficient of friction between road pavement and tries is 0.17, and the perception time is 3/4 seconds.arrow_forwardA car traveling at 45 mph on a poor, wet pavement has a braking efficiency of 87%. The brakes were applied 100 feet before hitting an obstacle in the road. The road is uphill for 40 feet and then is level for the remainder of the way. The car had a maximum coefficient of road adhesion in the sloped portion of the poor, wet roadway and but as soon as it started going on the level portion its coefficient of road adhesion reduced to 0.3. Assuming that the car struck the obstacle at 30 mph, what was the grade of the hill? Assume practical stopping distance equation applies.arrow_forwardA car is traveling up a 1.5% grade at 65 mi/hr on good, wet pavement. The driver brakes to try to avoid hitting a cone on the road that is 300 ft ahead. The driver's reaction time is 1.5 second. When the driver first applies the brakes, a software flaw causes the braking efficiency to lower to 0.8 for 100 ft. After the initial 100 ft, the braking efficiency returns to 1.0. How fast will the driver be going when the cone on the road is hit if the coefficient of rolling resistance is constant at 0.015? (Assume minimum theoretical stopping distance and ignore aerodynamic resistance.)arrow_forward
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