Due Homework February 16, 2007
Please read the handout given in class Analytical Tools Used to Evaluate Accidents and Chapter 4 in Saferstein. Based upon this reading and class discussions, answer the following questions.
1. A car skidded on the roadway that has a coefficient of friction with the road of 0.7. A police officer measured the skid marks and noted them to be 100 feet long. Two years later at a trial, the lawyer for the driver argues that the officer did not measure the skid marks correctly. He asserts, based on photographs, that the skid marks were no more than 92 feet long. Is the difference significant? 2. In analyzing a vehicular accident, reliance upon verifiable physical evidence should be primary. Give examples of verifiable physical evidence. 3. In most vehicular accident cases, eyewitness testimony is usually gathered and recorded. Explain why this type of evidence should be evaluated with caution. 4. Apply the Energy Method to solve the following. On low beams, a car has headlights that clearly illuminate the roadway 155 feet ahead but no farther. If the coefficient of friction between the road surface and the cars tires is 0.65, how fast can the driver go and still be able to brake to a complete stop when his lights first show a deer in the roadway? 5. Car A weighing 3217 pounds and traveling at 30 miles per hour impacts the rear end car of B that also weighs exactly 3217 pounds. Car B was not moving; it was stopped. The two cars stick together after impact. During the impact, the driver of car B mashed on his brakes and left a skid mark. The driver of car A allowed his car to roll freely after impact; the engine was no longer powering his car, and his car did not leave any skid mark. How long was the skid mark of car B? The coefficient of friction is 0.7. Ignore energy dissipation that might occur in crushing damage to the two cars. 6. Data taken from a vehicles black box are as follows. At 0 seconds the air bag was deployed upon impact with another vehicle. Assume that the coefficient of friction with the pavement is 0.72. Item Speed Brakes Throttle RPMs a. b. c. 4 sec. 71 mph Off 100% 3000 3 sec. 70 mph Off 100% 2960 2 sec. 69 mph Off 100% ...