The “Physics of Going 5 Over”: How Speed Impacts Car Crashes


LANSING, MI (WLNS)- Last night, lawmakers approved a plan that could increase speed limits up to 80 miles per hour in some places in Michigan. The bill will now move to the full House for a vote.

But knowing that almost everyone speeds sometimes, we wanted to know how higher speeds affect the severity of car crashes — the so-called “physics of going 5 over.”

Car crashes — they can happen anywhere — at any time.

First Lieutenant Joseph Thomas of the Michigan State Police says driving at higher speeds is the biggest problem.

“In the State of Michigan, people often feel that they are allowed five or ten miles an hour over the speed limit,” Lieutenant Thomas said. “That’s not the case.”

Proposed legislation could increase speed limits on hundreds of miles of highways across the state.

But how much does your driving speed affect how bad a car crash can get?

“If you increase your speed 10 percent from 70 to 77, the severity of the car crash – all other things left equal – increases by 21 percent,” said Wolfgang Bauer, a professor of physics and astronomy at Michigan State University.

Bauer says speed is important — and it’s directly related to kinetic energy.

“Any moving object has energy just by the fact that it’s moving,” Bauer said. “We call that kinetic energy.”

In this case, that moving object is your car. Bauer says when you double your driving speed, you quadruple you car’s kinetic energy.

And according to a 2015 report by the Michigan Department of Transportation, an increase in kinetic energy is associated with an increased risk of being in a car crash.

But Lieutenant Thomas says in any situation, you should always wear a seatbelt.

“Being belted will help you minimize your risk of severe injury during a crash – no matter what the speed,” Lieutenant Thomas said.

A simple way — to stay safe on the road.

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