Vehicle safety all starts with the seat you are sitting in.
The Most Common Injury In Crashes is…?
The single most common injury to people riding in a vehicle is neck sprain and the most effective tool to combat this injury is a good seat design. Testing agencies like the Insurance Institute For Highway Safety (IIHS) always include a head restraint test among the many they conduct for this very reason. When IIHS began testing for proper headrest geometry in 1995, only 3% of vehicles tested earned a score of Good. 82% were rated Poor.
The results of IIHS’ testing led the U.S. government to mandate changes to the way car seat headrests are designed. Today, most vehicle seats that IIHS tests earn a rating of Good, and the majority of the rest earn a score of Acceptable. That doesn’t mean that IIHS and automakers take a good result for granted. A score of less than Good disqualifies a vehicle form earning the coveted IIHS Top Safety Pick designation. It happened to the BMW i3 electric car just this past year. However, the many ways that the seat you sit in protects you from injury goes way beyond just whiplash prevention.
Side Impact Airbags Are In Your Seat
One of the most deadly crash types is a side-impact crash. The B-pillar on almost every modern car is now reinforced and helps prevent intrusion into the passenger compartment. However, the force of the blow would still badly injure or kill an occupant were it not for the torso airbags that inflate and reduce the impact forces dramatically. The torso airbag is mounted inside your car seat on the outer bolster. It can deploy in a fraction of a second and works in conjunction with the curtain airbag that drops from the ceiling to protect the occupant’s head. The next time you consider buying a car seat cover, keep in mind that covering up the special tear-away stitching in your car seat over the airbag may not be a wise decision.
Frontal Impact; Belts and Submarining
In a frontal crash, the seat a passenger sits in plays a vital role. The steering wheel or dash airbag, knee airbags, and seatbelts are all counting on the occupant to be in the spot they expect in order to work. Seats are designed to position an occupant properly so that these systems can all do their jobs as expected. Should a passenger be allowed to slip downward, an event called submarining, the plan goes awry. So designers ensure proper thigh support and elevation off the floor so that the other safety systems, both active and passive, will be effective. Knee airbags are not designed to just protect knees from being hit by the dash. Rather, their job is to push against your knees, and thus your femurs, and in turn, your hips, so that you stay positioned upright in the seat properly.
Your seatbelt plays a huge role in protecting you in any type of crash, but in a forward crash, it does much more than lock into one position. When a crash begins, or even when a vehicle begins to brake, a modern seatbelt will tighten to reduce slack. Step two in this elaborate process involves a pyrotechnic charge that fires and yanks on your belt to “pretension” it tight against your body. In step three, the occupant moves forward violently against the belt. Belts could cause more harm than good in extreme crashes, so they are designed to give a little at the end of the instant the crash occurs. Pretensioners and load limiters can be mounted in the B-pillar or can be attached to the female seat belt anchor attached to the lower part of the car seat. Check out the video above to get a feel for the complexity of these systems.
Off-side Crash Protection
One of the newest innovations in crash safety is an airbag system that deploys between the two front passenger seats of a vehicle. The force of a side impact can cause the two passengers to violently slam into one another. NHTSA found in a study that 11% of fatalities in belted, non-rollover crashes were caused by this type of injury. To prevent that, GM and others are now installing an airbag that deploys from the inboard seat bolster. The first models to use the new technology were the 2013 Buick Enclave, GMC Acadia, and Chevrolet Traverse.
The Future Of Protection
Almost all of the safety advancements we have overviewed apply to just the front seats in a vehicle. Although side airbags are now common in the second and third row of vehicles today, many of the other technologies are still migrating back to the rear passenger area. For example, Subaru, long a leader in active safety, has just this year introduced pretensioners and force limiters to the back outboard seats in the all-new 2018 Crosstrek. Going forward, we expect to see more automakers following this lead.