### A Day in the Life of John Henry, A Traffic Cop

Page 2

The sketch of the accident scene is shown above. Main street, a thoroughfare, has a 45 mile per hour speed limit. State Street also has a 45 mile per hour limit, but has a stop sign on either side of the road. Vehicle 2, which weighs 5800 lbs, skidded for 24 feet before coming to a stop next to the utility pole, marked Dec #20. Vehicle 1, which weighs 2060 lbs, showed no skid marks after the impact and came to a rest next to the house on the corner. Looking at the impact areas of the cars, it was clear to Lt. Henry that the cars impacted at right angles, hitting the front right bumper of vehicle 2 and the front left bumper of vehicle 1. After impact, they initially were traveling in the same direction. Lt. Henry noted that the weather was clear and sunny, 69o and the roadway was dry.

Before John Henry got any further in his analysis, he was informed that driver who was unconscious at the scene of the accident died at the hospital. Can you make an educated guess about which driver died based on the evidence so far? Justify your answer.

Why would John Henry note the weather and the condition of the road?

Why did vehicle 1 travel further than vehicle 2?

John Henry has to determine whether the driver of vehicle 2 ran the stop sign and/or if the driver of vehicle 1 was speeding.

Outline a procedure that Lt. Henry can use to answer these important questions. Be sure that your reasoning is sound, since he will have to testify in court on the evidence.

Does John Henry have all the information he needs to determine the velocities?

Go to Page 3.

 "http://www.udel.edu/pbl/curric/acc12a.html" Last updated Nov. 22, 1996. Copyright Barbara Duch, Univ. of Delaware, 1993.