The Insurance Institute for Highway Safety’s video below shows what it looks like in a 35mph crash when an adult in back is riding without a seat belt. This 170 pound crash test dummy weighs about 4,000 pounds (170lbs x 25G’s)… and makes a pancake of the driver.

Moral of the story: Everyone, everywhere, including in the back seat and way back, needs to wear their seat belt on every trip!

Studies published in peer reviewed journals on the topic:

Mayrose J, et al. The effect of unrestrained rear-seat passengers on driver mortality. J Trauma. 2006 Nov;61(5):1249-54.

  • CONCLUSIONS: Unrestrained rear-seat passengers place themselves as well as their driver at great risk of serious injury when involved in a head-on crash.

Mayrose J, et al. Influence of the unbelted rear-seat passenger on driver mortality: “the backseat bullet”.  Acad Emerg Med. 2005 Feb;12(2):130-4.

  • CONCLUSIONS: Adjusting for confounders (other than point of impact), the odds of fatality for a belted driver in a head-on crash was 2.28 times greater (95% CI = 1.93 to 2.7) with an unbelted rear-seat passenger. Unrestrained rear-seat passengers place themselves and their driver at great risk of fatal injury when involved in a crash.

Broughton J. The actual threat posed by unrestrained rear seat car passengers. Accid Anal Prev. 2004 Jul;36(4):627-9.

  • CONCLUSIONS: The results suggest that the risk of death to a front seat car occupant is increased by about three-quarters by the presence of an unrestrained rear seat passenger behind them.

Shimamura M, et al. Method to evaluate the effect of safety belt use by rear seat passengers on the injury severity of front seat occupants.  Accid Anal Prev. 2005 Jan;37(1):5-17.

  • CONCLUSIONS: The number of killed or seriously injured drivers is estimated to decrease by around 25% if rear seat occupants come to wear seat belts. Also, the number of killed or seriously injured passengers in front seats is estimated to decrease by 28% if unbelted rear seat occupants come to wear seat belts. Thus, wearing of seat belts by previously unbelted rear seat passengers is considered effective in reducing not only injuries to the rear seat passengers themselves but also injuries to front seat occupants.

Cummings P, Rivara FP.  Car occupant death according to the restraint use of other occupants: a matched cohort study. JAMA. 2004 Jan 21;291(3):343-9.

  • CONCLUSIONS: A car occupant could be killed if struck by another occupant who was catapulted forward, backward, or sideways in a crash.  The risk of death was greater for a restrained front seat occupant in front of an unrestrained rear seat passenger compared with a restrained front seat occupant in front of a restrained rear seat passenger (adjusted RR, 1.20; 95% confidence interval [CI], 1.10-1.31). Persons who wish to reduce their risk of death in a crash should wear their own restraint and should ask others in the same car to use their restraints.
    • CONCLUSIONS: The risk of death of belted front-seat occupants with unbelted rear-seat passengers was raised nearly five-fold. If rear seat belts had been used, almost 80% of deaths of belted front-seat occupants could have been avoided. Rear seat belt use should be encouraged for the safety of all car occupants.