The Physics of Car Crumple Zones: How Do They Work?

Vehicle parts should ideally be sturdy enough to bear the impact of a collision and keep occupants safe. Interestingly, there’s a good reason for some parts to be the opposite. The presence of less rigid crumple areas in your car can actually reduce impact during an accident.

What Is a Crumple Zone?

Crumple zones in cars refer to areas that are specially engineered to break down upon impact. These crush zones are usually at the front and rear of the vehicle.

How Do Crumple Zones Work?

Keeping people safe during car crashes is tricky, even with safety measures like seatbelts and airbags in place. To make the impact of collisions less devastating to passengers, engineers tapped into physics and designed crumple zones. Here’s an example of how they work:

Let’s say a vehicle is traveling at a speed of 60 mph when it suddenly crashes into a post.

Based on the law of inertia, the occupants will continue to travel at this speed until they hit something that stops them (window or dashboard). Traveling at that speed means that there’s a high chance that they’ll be severely injured, especially if they hit hard surfaces.

Engineers aimed to take away the force from the occupants when they created crumple zones. To accomplish that, they have to redistribute the force before it can reach the driver and the passengers.

Their solution? Create a buffer zone so that it’ll take longer for the vehicle to completely stop. In this way, there will already be a decrease in kinetic force before the impact reaches the occupants.

What’s In a Crumple Zone?

The materials used for crush zones or crumple zones vary depending on your ride’s automaker. There’s not much information online about them because these details are usually considered proprietary information.

Simple crumple zone designs include frame segments engineered to bend or collapse during a crash. On some vehicles, the steering column is also designed to collapse to reduce impact. Some automakers use metals to absorb kinetic energy. Plastic and plastic composite materials are also perfect for crumple zones because they’re lightweight.

Crumple Zone Testing

Institutions like the National Highway Traffic Administration (NHTSA) and the Insurance for Highway Safety Institute (IIHS) perform vehicle crash tests.

The NHTSA rates how a vehicle performs in a front-end collision, assigning a rating from one to five stars based on the outcome of the crash test. Most crumple zones are at the front end of the vehicle, so you can use this rating to assess how effective a particular vehicle’s crumple zones are.

When Were Crumple Zones Invented?

Crumple zones were introduced in the 1950s. Béla Barényi, an engineer who worked for Daimler-Benz, integrated them on the Mercedes-Benz W111 Fintail in 1959.

Other Car Safety Features That Can Save Lives

Aside from crumple zones,  here are other safety features you can find on cars:

Airbags

Airbags automatically inflate during severe front-end and side collisions, cushioning occupants from the harsh impact. Some modern vehicles feature thorax airbags with head protection.

Seatbelts

If you’re not buckled up during a major crash, the impact might eject you from the vehicle, so always use your seatbelts. Secure them properly to avoid fractures, contusions, and other injuries.

Head Rests

Also known as head restraints, these parts come as a standard feature in all vehicles because they can reduce the risk of whiplash and similar injuries during a collision. They’re ideally at eye height or close to the back of the head for maximum protection.

Reverse Camera

A reverse camera is helpful when you’re parking or when you’re trying to safely exit your driveway without hitting something. If your vehicle doesn’t have one, there are a lot of aftermarket options available online.

Shatter-Resistant Glass

Glass usually takes damage during crashes, and it’s dangerous when it shatters to pieces. The sharp shards can add to people’s injuries. That’s why many modern windshields have shatter-resistant laminated glass, which can withstand impact without breaking to pieces.

Make-Specific Safety Features

Some automakers continue to find ways to ensure people’s safety during collisions. Consider Volvo’s Safety Ride Down concept.

Crumple zones are tricky to apply to compact cars because of their limited space. That’s why Volvo developed an additional impact-absorbing technology for small units like the Volvo 33C.

In this type of system, the seats are mounted on a sled-like structure equipped with shock absorbers. During a collision, the seats move forward at the same time the frontal crumple zone is deformed.

The shocks absorb the impact, slowing down the seats’ movement. The steering wheel and a part of the dashboard will also move forward to accommodate the driver.

Stay Safe While On the Road

Driving always comes with risks, and it can be comforting to know that many safety features can help lessen your injuries during a collision. However, you shouldn’t rely on crumple zones or other safety features to keep your passengers safe.

The best thing to do is to practice safe driving and pay attention to your surroundings to avoid getting involved in a collision. Avoid driving when you’re under the influence of alcohol. Make sure to focus on the road, and avoid any distractions.