Car seat laws for older kids have limited impact

The same parents who already were buckling up kids appear most likely to switch to safety seats, leaving the same number of kids unrestrained, found a study published in the Journal of Policy Analysis and Management.

"These laws can be very appealing for legislators to pass, but our research calls into question their value," said Lauren Jones, lead researcher and assistant professor of consumer sciences at The Ohio State University.

"Our study suggests that safety-conscious parents are likely to do what makes their child the safest but these laws don't have much effect on other parents."

Furthermore, higher fines (which reached as much as $500 as of 2016) didn't appear to make much difference in raising the likelihood parents and other drivers complied with the laws, the study found.

In the last four decades, laws throughout the United States have steadily increased mandatory safety seat restraint ages. In the 1980s and 1990s, safety seat laws were the norm for kids up to age 2 or -- at most -- 3. By 2012, the average upper age requirement was 6 years old.

About 17 percent of children 7 years old and younger were in car safety seats before new laws expanded age requirements. That percentage jumped from 27 percent to almost half after stricter laws took effect, the researchers found.

But the percentage of unrestrained children -- those with neither a seatbelt on nor strapped into a car seat -- barely moved.

The new study found evidence that the laws saved lives, but that data was limited, Jones said. A best-case estimate showed that between one and 39 children may have survived annually because of safety seats.

"I think the laws have probably reduced fatalities, but probably not as much as most parents would assume," Jones said. "Thank goodness childhood car crash deaths are something that happens relatively infrequently, but that also makes it harder to evaluate."

Importantly, this study did not examine injuries or severity of injuries before and after passage of stricter laws. It's possible that children's injuries have declined because of more widespread use of safety seats, Jones said.

Jones and Nicolas Ziebarth of Cornell University used a national database of fatal crashes from 1975 to 2011 to examine "before" and "after" restraint use and fatalities.

To improve the quality of their evaluation, they analyzed law-mandated child safety seat use against use in three other groups: children in different states in the same year, children in the same state in different years and older children in the same state during the same year.

Regardless of the analysis, there was no evidence that safety seat laws significantly changed the percentage of children who go unrestrained, prompting Jones to conclude that resources might be better spent elsewhere.

The research estimates the net annual cost of the safety seat laws at $377 million. The researchers factored in 39 saved lives at an estimated value of $390 million per year and a cost of $200 per safety seat, or $767 million a year. Their rough estimate does not include other potential safety benefits, including reduced injury rates.

"It's not a costless piece of legislation, especially for low-income families," Jones said. "Education, particularly of young parents, and resources to help them afford seats could be more impactful policy tools."