Car Crash Speeds: Injuries Occur at Surprisingly Low Speeds.
Car Accident Speeds Can Be Hard to Determine and Most People Have No Clue What a Particular Speed Looks Like or What a Collision at any Given Speed Results In
Live human crash studies have shown that the human neck can be injured with a head velocity of 2.5 mph. It does not take much of a crash to get the head to achieve that number. In fact, researchers show that the average collision that causes injury is 12 mph. At 12 mph it is doubtful you will see much damage to your vehicle, but when you are in a vehicle that is struck at 12 mph you will have no doubt you were hit.
When I consult with patients and tell them they were involved in a high speed crash because I think the other vehicle hit them at about 25 mph they laugh. Not because I say high speed, because they definitely “feel” it was because they have head and neck pain and I just showed them x-rays that reveal torn ligaments. They laugh because I say 25 mph is “high speed.” They say “it must’ve been 40 or 50 at least.”
The fact is, cars get pretty mangled at speeds over 25 mph. At 40 mph many cars are totally destroyed. The thing to keep in mind is, the person that endured a 25 mph crash with extensive vehicle damage, may have had less g-force to their neck than someone hit at 16 mph.
“How can that be?” you ask. The answer is simple: crush.
If two cars collide and they both suffer vehicle damage: crushed plastic, bent metal, folding parts that all dissipates kinetic energy of the crash resulting in less energy to the occupant. If neither car deforms then more energy is left over to affect the occupant. Lower speed collisions involve little vehicle damage and relatively higher bodily injury. A Japanese study showed that crash victims were more likely to require prolonged treatment and had higher complication rate if their vehicle showed no damage as a opposed to those suffering a vehicle that was a total loss. The study showed that with higher vehicle damages, less treatment was required.
The biggest predictors of injury are angle of impact (rear-end impact is worst), awareness, bumper alignment, head restraint position, occupant posture, occupant gender, size and health.
With that said, here are some examples of crashes at 5 mph, 7 mph, 9 mph and 11 mph. These are examples of well aligned bumpers that give maximum protection. Note the dummy’s head movement and the body movement after the head has hit the head restraint. Also note the lack of vehicle damage. The videos may surprise you.
Each of the above collisions have the potential to cause injury to the occupant despite the lack of vehicle damage. A general rule I use when investigating a collision is that if there is obvious vehicle damage in a rear-end impact, the speed must have exceeded 10 mph. That is based on studies that showed the speeds required to cause any damage on a rear bumper. Most vehicles studied did not show damage below 10 mph, many cars required 12 mph and some as high as 20 mph.
If you see a crash on the side of the freeway and the struck car looks really bad, you may think the collision was at a very high rate of speed. Consider the following video which shows what 2 cars look like after a 24 mph rear impact auto collision.
If you saw these cars or worse, you were in the silver one, you’d be shocked to find it was “only” 24 mph. You’d also be shocked to learn that the occupant change in velocity was 13 mph. Recall that the human threshold for injury is 2.5 mph velocity. So this 24 mph collision caused a force to the occupant 5 times (500%) greater than the minimum needed to cause injury. A slow speed crash of only 11 mph in which no vehicle crush is observed could render a velocity of 5 mph to the occupant; definitely enough to cause an injury. Low speed crashes do cause injuries.
No matter the speed, if you suffered a car collision and have questions or have pain, call me (714) 938-0575. I’m Dr Barry Marks Chiropractor, and I have been specializing in the diagnosis and treatment of car accident injuries since 1986 and have extensive experience and training in this field. I can help you not only get better, but also assist you in filing your claim and knowing what to do.