I’m asked periodically which is the best position for the seat in your car. I find it funny to drive around town and to see so many drivers with their seat reclined so far back that it is reminiscent to sitting in a lazy-boy recliner. As comfortable as this may be when riding as a passenger, it is a recipe for disaster if there ever was a crash. Why?
The answer lies within geometry and physics.
I want you to visualize someone driving their car with their seat back reclined. Can you picture it yet? Now make sure that you hear the bass of the music as they drive by. Now picture how much space is between the shoulders and the back of the seat? If the back of the seat is reclined, it creates too much space between the head restraint and the back of the head. This measurement in my world is known as the “backset”. The one thing that we do not need is the potential of having the head launched backwards into the head restraint. This creates velocity. Velocity coupled with poor “head restraint geometry” causes injury. There is another critical measurement that will affect injury. The other geometrical problem is the other measurement known as the “Topset.” This is the measurement of the top of the head in relation to the top of the head restraint.
If the Topset is too low, the head now has a chance of being whipped over the top of the head restraint. If you have ever seen a bullwhip crack and break the sound barrier, you can now make a similar comparison to your head and neck. What’s worse are the older vehicles that didn’t even have head restraints. I feel for those occupants. There is a much greater chance of injury to neck, but now add injury to the middle and upper back. Sadly, those bones are not designed to flex backwards.
Whiplash occurs because the head is moving too fast and is not prevented from going over the top of the head restraint. When you have your seat back in reclined position, regardless if it is “Gangsta” level, or just slightly reclined, your neck is incredibly vulnerable.
So is it cool to drive looking like grandma, with your seat back in an upright position? Maybe not, but at least you may prevent getting whiplash.