The Physics of High Speed Auto Accidents

By Staff Attorney
The Gasper Law Group, PLLC

High Speed Collision - 05-05-16

Every time you drive or go for a ride in a vehicle, you are subject to Newton’s Laws of Motion. Newton’s First Law states that a vehicle’s speed and direction will remain constant unless acted on by an external force. Impact from an external force, like another vehicle, can cause serious bodily injury and damage to your vehicle. The extent of the injury/damage depends on the magnitude of the force and the location of the impact. Modern cars come equipped with bumpers, airbags, and other safety features to mitigate the effects of impacts by extending the deceleration period during a crash and thus reducing the force on drivers and passengers inside the vehicle.

Let’s take a closer look at some of the critical physics at play.


Newton’s Second Law states that force is equal to mass times acceleration. This is why vehicles that travel at fast speeds are more likely to be involved in horrendous crashes. It’s not the “fast speeds” themselves that are the problem. It’s the size of the change in those speeds that causes the force. That’s a crucial distinction. If that sounds confusing, consider this more concrete explanation. Let’s say a car going at 80 MPH hits a pole on the side of the road. It takes just a fraction of a second for that car to transition from “zooming at 80 MPH” to “being still on the side of the road.” Now let’s say a different car going at only 40 MPH hits that same pole. It takes roughly the same amount of time for that car to stop. In other words, the change in velocity in the first accident was twice as big; hence, the force imparted on the vehicle and its occupants is likewise twice as big.

Kinetic Energy and Mass

Kinetic energy is the energy of motion, and it has a linear relationship with mass. For example, a truck twice the size of an average sedan has twice as much kinetic energy. Kinetic energy has an exponential relationship with velocity, meaning that increasing your speed will dramatically increase kinetic energy. When you hit the brakes, this kinetic energy is dissipated through heat. In the case of a collision, the bending and crumpling of metal from the outside of the vehicle dissipates energy.

Accident Reconstruction

According to the National Highway Traffic Safety Administration (NHTSA), an automobile accident occurs every five seconds somewhere in the United States. Although most accidents are minor, a substantial portion lead to either criminal or civil legal action. Accident reconstruction reports, which use the principles of physics we’ve discussed to determine what happened and which party, if any, was at fault, can be important pieces of evidence.

If you have been involved in an automobile accident, our experienced attorneys can help investigate what happened and develop an effective strategy to help you obtain fair and complete compensation. Contact the Gasper Law Group today at 719.227.7779 for a free consultation.