why consumer cars have crumple zones for safety yet racing cars have roll cages


It’s always struck me as odd that crumple zones help absorb impacts which makes cars safer. Yet race cars have roll cages which make them safer.

In: 187

Mainly because race cars are all headed in one direction and it’s more for roll safety whereas consumer cars have to watch out for oncoming traffic and animals.

So the crumple zones help to reduce impact by slowing you down…. Slower lol. “In an accident there are 3 things in motion. The car, you, and your organs!” -mythbusters

Most consumer cars are not designed for high speed impacts higher than 60-75mph those crumple zones are designed more for rear ends and side impacts.

Race cars by design are high speed vehicles that can easily impact at 100mph or more. A crumple zone on a race car would do next to nothing. The roll cages are desinged to strengthen the cab in the event of a high speed impact where the chances of flipping are higher.

Both types of cars have “cages” around the occupants, to make sure the occupants do not get squashed during a crash. And both types of cars have sections outside the cage that are designed to absorb the energy of the crash.

If you look at an [exploded diagram](https://www.behance.net/gallery/15717037/FORMULA-E-CAR) of an F1 racing car, you’ll see that the there is a center body section where the driver sits inside. This section is usually a solid piece of carbon fiber, and acts as the roll cage. The pointy nose in front of it acts as a crumple zone; you can see it in action in this [crash test video](https://youtu.be/Yw56mgPK43s?t=90). Other parts like the wheels & suspension are also designed to break off in a crash, which helps dissipate energy.

Similarly, if you watch any [crash test video](https://www.youtube.com/c/RealSafeCars) of a modern car, you’ll see that the car body around the driver/passenger compartment remains intact. That’s your “roll cage.”

Consumer cars have much larger crumple zones because the occupants aren’t as well protected. A racing car driver is secured with a 5-point harness and protected by a helmet. On some racing cars, the helmet is secured to the seat. All this means the driver can survive a high-speed crash with a much smaller crumple zone.

p.s. Consumer cars didn’t always have crumple zones & passenger cages. Modern cars may not look any safer than old cars, but [this crash test video](https://youtu.be/fPF4fBGNK0U?t=14) shows why modern cars are so much safer.

Race cars are basically a large crumple zones with a roll cage around the passenger compartment. They are built to be super lightweight, and their body will act as a crumple zone quite nicely on impact, absorbing much of the impact of a crash.

The roll cages in race cars are built just immediately around the driver to help ensure that part does not crumple. The lower speeds of consumer cars means that the weaker reinforcement from the main frame is typically enough, and there is less risk of a full roll that really needs a roll cage.

In addition to the other comments, there are a few differences.

In any car racing sport, the driver is VERY firmly attached to the seat with multipoint seatbelts. These seats are also tightly secured to the floor and, sometimes, the roll cage directly. In high speed impacts, this arrangement doesn’t allow ejection from the cage and, in many cases, it is hoped that the design of the track allow for a lot of sliding and rolling to dissipate the excess energy on the relatively light vehicle.

Typical cars and their occupants are seldom as well attached and are much heavier. The crumple zones and air bags “take up” the additional movement and reduce the energy transmitted to the occupants (who might be flying around). The purpose here is practical protection over a much wider variety of collisions. A properly designed roll cage and safety seats would be VERY inconvenient for normal car occupants (who also don’t wear helmets as well as head and neck protection equipment) as ingress and egress are very badly compromised.