A driver is traveling at 90 mi/h down a 3% grade on good, wet pavement. An accident investigation team noted that braking skid marks started 410 ft before a parked car was hit at an estimated 45 mi/h. Ignoring air resistance, and using theoretical stopping distance, what was the braking efficiency of the car? If the car’s antilock-braking system was effective (no sliding wheels on the pavement), what would the crash speed be

A driver is traveling at 90 mi/h down a 3% grade on good, wet pavement. An accident investigation team noted that braking skid marks started 410 ft before a parked car was hit at an estimated 45 mi/h. Ignoring air resistance, and using theoretical stopping distance, what was the braking efficiency of the car? If the car’s antilock-braking system was effective (no sliding wheels on the pavement), what would the crash speed be

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter3: Characteristics Of The Driver, The Pedestrian, The Bicyclist, The Vehicle, and The Road

Section: Chapter Questions

Problem 11P

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Similar questions

A driver is traveling at 90 mi/h down a 3% grade on good, wet pavement. An accident investigation team noted that braking skid marks started 410 ft before a parked car was hit at an estimated 45 mi/h. Ignoring air resistance, and using theoretical stopping distance, a. If the car’s antilock braking system was effective (no sliding wheels on the pavement), what would the crash speed be?
A driver traveling down a 4% grade collides with a roadside object in rainy conditions, and is issued a ticket for driving too fast for conditions. The posted speed limit is 65 mi/h. The accident investigation team determined the following: The vehicle was traveling 40 mi/h when it struck the object, braking skid marks started 205 ft before the struck object, the pavement is in good condition, and the braking efficiency of the vehicle was 93%. Using theoretical stopping distance, assuming aerodynamic resistance is negligible, and with the coefficient rolling resistance approximated as 0.015, should the driver appeal the ticket? Why or why not?
A student trying to test the braking ability of his car, determined that he needed 32 ft. More to stop his car downhill on a particular road than uphill when driving at 55 mph. Assuming that the coefficient of friction between the tires and the pavement is 0.30. Determine the braking distance downhill and the percent grade of the highway at that section of the road.
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]
A car is approaching toward an intersection with speed 45 mph. The road has a downhill grade of 1%. When the car is at a distance of 250 ft from the intersection, the signal turned yellow. If the driver applies brake and the reaction time of the driver is 1.5 s, will the driver be able to come to a complete stop? Justify your answer with calculations. Assume braking friction coefficient of 0.35.
A level test track has a coefficient of road adhesion of 0.80, and a car being tested has a coefficient of rolling friction that is approximated as 0.018 for all speeds. The vehicle is tested unloaded and achieves the theoretical minimum stop in 180 ft (from brake application). The initial speed was 60 mi/h. Ignoring aerodynamic resistance, what is the unloaded braking efficiency?
A 11120 N car is designed with a 310 cm wheelbase. The center of gravity is located 60 cm above the pavement and 105 cm behind the front axle. If the coefficient of road adhesion is 0.6, what is the maximum tractive effort that can be developed if the car is (a) front-wheel drive and (b) rear-wheel drive? From the previous question, how far back from the front axle would the center of gravity have to be to ensure that the maximum tractive effort developed for front- and rear-wheel drive options is equal?
a vehicle was stopped in 2.1 seconds by fully jamming the brakes and the skid mark measured 10 meters. Determine the average skid resistance on the level pavement surface.
1. Compute the braking distance for a car moving at an initial velocity of 60kph and a final velocity of 40 kph. slope of roadway is +5% Coefficient of friction between the pavement and tires = 0.15 perception-reaction time = 3/4 sec
If the car in Example 2.9 had CD = 0.45 and area = 25 ft2, what is the difference in minimum theoretical stopping distances with and without aerodynamic resistance considered (all other factors the same as in Example 2.9)? Example 2.9 EFFECTS OF GRADE ON THEORETICAL MINIMUM STOPPING DISTANCE A car is traveling at 80 mi/h and has a braking efficiency of 80%. The brakes are applied to miss an object that is 150 ft from the point of brake application, and the coefficient of road adhesion is 0.85. Ignoring aerodynamic resistance and assuming the theoretical minimum stopping distance, estimate how fast the car will be going when it strikes the object if (a) the surface is level and (b) the surface is on a 5% upgrade.
a 2500-lb car designed with a 120-inch wheelbase. the center of gravity is located 22 inches above the pavement and 40 inches the front axle. if the coefficient of road adhesion is 0.6, how far back from the front axle would the center of gravity have to be to ensure that the maximum tractive effort developed for front- and rear- wheel-drive option is equal?
A driver is traveling at 45 mi/h and has a perception-reaction time of 3 seconds. A deer is spotted at a distance of 380 ft ahead and the driver is able to come to a stop just before hitting the deer. Assuming practical stopping distance, what is the grade of the road in percent?