Williamsport High School
Williamsport, Maryland
Introduction
Using the equations of kinematics, students build a STELLA model representing one car following another on the highway. The problem is to find the safest following distance based on reaction time, velocity and braking rates. This following distance is then compared to the popular two second rule and one car length per 10 mph rule, and reasons for differences are discussed.
A STELLA model representing the Kinematics of Tailgating:
This graph represents two cars going 65 mph, with 28 ft/sec^2 braking rate, and .45 second reaction time, 4 car lengths between them:
2.5 car lengths:
3 car lengths:
