(Reuters Health) - Drivers who don’t wear seatbelts are more likely to skip seatbelts and car seats for their kids, an analysis of U.S. crash data suggests.

When the driver in a crash wasn’t wearing a seatbelt, young passengers up to age 15 were 16 times more likely to also be unrestrained than when drivers were buckled up, the study found. And when drivers went without seatbelts, passengers ages 16 to 19 were about 53 times more likely to be unrestrained.

“Often times, young passengers do not and cannot make the decision to be properly restrained - it is the driver’s responsibility,” said lead study author Douglas Roehler of Rush University Medical Center in Chicago.

“If the driver in a crash with a child passenger is not making the safe decision for themselves, we found that they were less likely to make safe decisions for their young passengers,” Roehler said by email.

Parents should put infants and toddlers in the back seat in rear-facing car seats as long as possible, at least until they’re around 2 years old or too large or heavy to fit in that position, according to the American Academy of Pediatrics (AAP).

After that, children should remain in the back of vehicles in front-facing car seats as long as possible, until they reach the weight and height limits for the seats. Many seats can work until kids weigh about 65 pounds.

When children can no longer use car seats, they should switch to booster seats until the vehicle’s lap and shoulder belt fit properly, which may happen when children are at least 4 feet 9 inches tall and 8 to 12 years old, according to the AAP.

For the study, researchers examined nationwide data on fatal and nonfatal crashes involving passengers aged 19 and younger from 2011 to 2015.

In a sample of all crashes during this period involving a fatality with a child passenger present, 32 percent of children up to age 8 died, 34 percent of 9-15-year-old passengers died and 40 percent of 16-19-year-olds died.

At the national level, the researchers calculate, about 25 in every 1,000 kids aged 8 and younger were killed as unrestrained passengers in motor vehicle crashes, as were 42 in every 1,000 youth 9 to 15 years old and 38 in every 1,000 teens aged 16 to 19.

In both fatal and nonfatal crashes, boys made up more than half of the unrestrained young passengers age 15 and under, but girls made up the majority of unrestrained passengers in crashes involving older teens in the study.

One limitation of the study is that researchers lacked data on the type of restraints used by passengers, making it impossible to know if infants were properly placed in back seats in rear-facing seats or if the oldest teens who did use seatbelts used both the lap and shoulder belts.

The study also only looked at fatal crashes and nonfatal collisions requiring tow trucks, leaving out less-severe crashes.

Still, the results suggest stricter state laws around driver seatbelt use may have an added benefit of increasing the chance that young passengers will be properly restrained, the authors conclude.

“Drivers who wear a seatbelt are likely more to be safety conscious when riding in a motor vehicle,” said Dr. Lois Lee, a pediatrics and emergency medicine researcher at Harvard Medical School and Boston Children’s Hospital who wasn’t involved in the study.

“They may also be more aware of seatbelt laws in their state,” Lee said by email. “As a result, they are more likely to be aware of recommendations for safe driving with children and will exhibit safety behaviors involving their children.”

States generally require drivers to wear seatbelts and children to have seatbelts or boosters, but enforcement policies vary and may influence how seriously people take these rules, said David Schwebel, a researcher at the University of Alabama at Birmingham who wasn’t involved in the study.

“The take-home message for parents and other adults is that your children are watching you,” Schwebel said by email. “If you are safe - you wear your own seatbelt and you insist that your child use appropriate restraints - then your child will be safe, both in the immediate present but also in the long-term future.”

SOURCE: bit.ly/2SmUs63 Pediatrics, online February 4, 2019.