Part 4: Judgement Day

Officer Matthews received a more detailed report from the police accident investigator: The 1978 Ford was 30 feet into the intersection, coming to a stop close to the northeast corner of S. College and Delaware Avenue. The 1988 Chevrolet van was found directly behind the car. Both vehicles showed skid marks from the south side of the intersection to the position where they came to a stop. Our analysis showed that the Ford left an 80-foot skid mark prior to being struck by the van, while the van left a 20-foot skid mark prior to impact.

A drag sled was used to determine that the average deceleration on the road was 19 ft/s². The speed limit on S. College is 25 mph. The van weighs approximately twice the weight of the car, and since the car was stopped just prior to impact, speed of the van prior to impact was approximately 1.5 times the speed of the two vehicles just after impact.

Questions:

1. Sketch the intersection, position of the car and van, and appropriate skid marks.
2. Using what you know about reaction time, and stopping distance, how far from the intersection was Sandy when she first saw the students and yellow light?
3. Explain the sequence of events from the time Sandy first noticed the yellow light to the time when both vehicles came to a stop in the intersection.
4. Should either driver be charged with speeding? Justify your answer with data.
5. Was Jerry following too closely behind Sandy? Do we have data to help answer that question?
6. Should Sandy or Jerry be charged in the accident? Justify your reasoning.