A report released by NHTSA over the summer analyzing state and national data found that earlier use of child safety restraints for 3- and 4-year-old children resulted in less risk of injury than when using booster seats.
The NHTSA study focused on 17 years worth of experience in Kansas, Nebraska and Washington as well as the National Accident Sampling System Crashworthiness Data System from 1998 through 2007 to estimate the effects of early graduation from child safety restraint systems, or CSRSs, to booster seats and the early graduation from booster seats to lap-shoulder belts.
It found that the CSRSs could reduce non-disabling injuries all the way to fatalities by as much as 27 percent for 3- and 4-year-old children compared to when booster seats were used. Forward-facing CSRSs are recommended for 1- to 4-year-olds or until they reach 40 pounds. Booster seats are then recommended for passenger vehicles to elevate children 4 to 8 years of age so that lap/shoulder belts provide a better fit. Shoulder straps that ride too high may limit the ability to contain the child in the seat and may result in discomfort, while lap belts positioned too high may fail to engage the pelvis and could result in internal injury.
But the same does not go for school buses.
Two years ago, NHTSA’s curriculum “Child Safety Restraint Systems in School Buses” removed a chapter on booster seats because of the increased possibility of injuries, according to Charley Kennington, transportation director for Innovative Transportation Solutions at the Region 4 Education Services Center in Houston and lead instructor of the NHTSA safety seat course taught at industry conferences nationwide. Instead, a slide was added that indicates that booster seats are not to be used in school buses.
Lap belts installed in smaller Type A variety buses don’t protect the torso, so using a booster seat adds nothing to the safety of the child and could increase the risk of injury. Instead, four- or five-point harnesses should be used in those cases, Kennington added. And even when lap/shoulder belts are used, those systems in school buses already act like booster seats because they are adjustable, unlike those in regular passenger vehicles.