Objects In Motion: Defending The Tractor-Trailer Versus Passenger Vehicle Rear-End Collision

Sir Isaac Newton knew a thing or two about what happens to an object in motion. One of his observations: “Change in velocity depends on the mass of the object.” If only physics was included on a driver’s licensing exam.

A loaded tractor-trailer weighs 35 tons. The average passenger vehicle weighs two tons. Given that the velocity of a mass describes the rate of occurrence or action, will two masses (for this discussion, vehicles) having the same span of distance within which to employ deceleration (but having two completely different weights) arrive at the same location at the same time traveling at the same speed?

Anyone involved with automobile claims knows all too well the scenario of a passenger vehicle changing lanes into the path of a tractor trailer with only two car lengths (or less) of space between vehicles. Frequently this results in a rear-end collision, with the tractor-trailer not having enough distance for the needed reduction of speed to safely slow the truck.