Understanding the Physics of Your Car’s Crumple Zones

It may feel like that big car you’re driving is solid, and in most ways it is, but it may be designed to crumple. That’s right, and you want it to crumple, despite what your intuition is telling you.

Since they’ve been keeping statistics on motor vehicle incidents, the risk of being killed in an accident has decreased year-over-year. 2012 is a bit of an outlier, where fatality and injury rates were slightly above the prior year.

Why do we see improvement in injury and fatality statistics for car accidents each year? Because the vehicles we’re driving are safer, and one of these safety features is the crumple zone.

This means a car that crumples is good for you and your auto insurance premiums.

The science behind crumple zones

One of the reasons you may believe that a rigid design makes for a safer car is because that is how cars used to be made. It was believed in years past that a more rigid construction made for a safer vehicle.

However, physics has proven this to be incorrect. In fact, the laws of physics tell us that the passengers inside a vehicle traveling at 50 mph will continue to travel at 50 mph should the vehicle be brought to a sudden stop.

If the passengers keep moving while the vehicle has stopped, well, you get the picture … it’s not good.

The job of the crumple zone is to transfer some of the car’s kinetic energy into a “controlled deformation.” Of in terms you and I can understand, the car is designed to crumple at impact. J

This crumpling will most certainly cause greater damage to the vehicle, but if done correctly, crumple zones will severely reduce bodily injury to passengers.

Let’s take a closer look at how crumple zones work. During impact, the crumpling of the vehicle frame slows down the rate of deceleration of the vehicle, effectively lowering the force (on average) of the impact. This slowing of the force provides greater survival space for passengers (if you’re wearing your seat belts).

The concept of a rigid design is not entirely eliminated in modern cars with crumple zones. Crumpling works best in conjunction with a rigid occupant compartment, often called the “safety cage.”

You can see, while there is a bit of a trade-off between property damage and injury, the latter is much more acceptable. It just is better economically for all parties, not just those charging insurance premiums.

The history of the crumple zone

In 1959 Mercedes-Benz, a long-time engineer of innovative safety features for automobiles began to manufacture cars designed to absorb impact energy. Following suit, and with the introduction of safety ratings in the 1970s, nearly all automobile manufacturers began to adopt energy-absorbing technology.

Along with crumple zones, other design factors have helped to make cars safer. Seat belts, airbags, head restraints, and interior features redesigned to be more flexible, cushioned, and rounded all help to minimize injuries and protect drivers and passengers in a crash. In addition, more vehicles now come equipped with electronic stability control. Other new crash avoidance technology is emerging to help drivers avoid a collision in the first place.

Buying a safer car

If intend to buy a new or used car or a car for your teenage driver, a little research can help you select a car that meets all your needs … including safety.

Two respected national organizations, the National Highway Traffic Safety Administration and the Insurance Institute for Highway Safety have programs to rate vehicles for safety. Each organization provides annual ratings of the safety performance of automobiles in crashes.

In addition, third-party rating organizations can help you make a safer choice. Your insurance agent or insurance company can also provide tips for helping you choose a safer car.

The bottom line

Cars are much safer today than they have been in the past, and engineers continue to innovate in an attempt to create even safer vehicles. Each new innovation helps to reduce the overall cost accidents have on society, the least of which are auto insurance premiums.