Back Seat Safety

As you no doubt are aware, Force = Mass x Acceleration. And while this equation might seem like nothing but theory, the fact is that the laws of physics are unyielding. For instance, a 60-pound child in the back seat of a car traveling at a mere 30 miles per hour is involved in a sudden collision can exert as much force as a young elephant -- about 2,700 pounds -- if that child is unbelted and thrown forward in a sudden collision. That means a child can impact the windshield or a front-seat occupant with deadly force.

In 2005, 1,946 children age 14 or younger were killed while riding as passengers in motor vehicle accidents.  The Insurance Institute for Highway Safety reports that motor vehicle crashes account for one in three injury deaths among children, and crash injuries are the leading cause of death among 5-to-12-year olds. But, frightening as that is, all is not hopeless. Accidents will happen, but they don't have to become tragedies. According to the National Highway Traffic Safety Administration, an estimated 7,896 children under the age of five were saved from 1975 to 2005 by the use of safety belts and child restraints. Among passengers over the age of four, seat belts saved an estimated 15,632 during the same period.

Seat belts are the first and best line of defense in this battle. Massive injuries can result when vehicles stop or change direction suddenly as the result of a collision, and things can become far worse if the objects and occupants within the vehicle fail to change direction at the same time. If your car stops abruptly and passengers are unrestrained, they become potentially deadly projectiles.

"Restraints help people and cars move together," said Ingrid Skogsmo, director of safety for Volvo Car Corporation, Sweden "Imagine trying to keep your balance in a standing-room-only train car as it lurches forward suddenly or stops abruptly without something to brace yourself with."

It might be tempting to ignore this warning for short trips. After all, what could happen in a five-minute drive to school or the market?  Well, what could happen is tragedy. According to the National Safe Kids Campaign, 75 percent of all crashes occur within 25 miles of home. And most of those take place on roads with maximum speed limits of 40 mph or less.

"People are just full of reasons for not belting back seat passengers," Skogsmo said. "School's just three minutes away, we're just going to the grocery store, or just over to friend's house. We're full of excuses. But in the end, if we don't belt our children or for that matter any rear-seat occupant, we're setting them up for injuries or death. 'Sorry' doesn't go very far then."

The best advice is to buckle up your rear seat passengers every time you get into the car, because the seat belt can perform a life-saving function not just in an initial impact, but also it what follows. A car's seat belt keeps doing its job of helping to retain the occupant within the safety structure of the cabin after the initial impact has occurred, because accidents often involve secondary impacts and/or rollovers. It is the seat belts that help keep the rear-seated occupants strapped safely inside the vehicle until the energy of the accident has dissipated.

"During a roll-over the effect is very much like clothes in a washing machine during the spin cycle," Skogsmo said. "There are huge forces that can easily eject occupants who are not using a seat belt."

Boston-bred Driving Today Contributing Editor Tom Ripley writes about the auto industry and the human condition from his home in Villeperce, France.