(CBS/AP) Dr. Fred Henretig said, "I found myself being very nervous on the occasions that we drove our granddaughter around." Then the grandparent and emergency medicine doctor at Children's Hospital of Philadelphia "wondered if anyone had ever looked at this before."
Prompted by his experiences when his grandchild was born three years ago, Dr. Henretig led a study of children's injury rates in car crashes. And the study showed that kids are safer in cars when grandma or grandpa is behind wheel - and not mom or dad.
"We were surprised to discover that the injury rate was considerably lower in crashes where grandparents were the drivers," said Dr. Henretig. Previous evidence showed that car crashes are more common in older drivers, mostly those beyond age 65. But this study - published in the July 18 issue of Pediatrics - looked at injuries rather than who had more crashes. And it showed that children's risk for injury was 50 percent lower when riding with grandparents than with parents.
Researchers aren't sure, but they have a theory. "Perhaps grandparents are made more nervous about the task of driving with the `precious cargo' of their grandchildren and establish more cautious driving habits" to compensate for any age-related challenges, they wrote.
Northwestern University Professor Joseph Schofer, a transportation expert not involved in the research, said other unstudied circumstances could have played a role. For example, grandparents could be less distracted and less frazzled than busy parents dropping their kids off at school while rushing to get to work or to do errands. Driving trips might be "quality time" for older drivers and their grandchildren, Schofer said.
The results are from an analysis of State Farm insurance claims for 2003-07 car crashes in 15 states, and interviews with the drivers. The data involved nearly 12,000 children up to age 15. Only about 10 percent of kids in the study were driven by grandparents, but they suffered proportionately fewer injuries. Schofer noted that the average age of grandparents studied was 58.
"Grandparents today are not that old" and don't fit the image of an impaired older driver, he said. "None of us should represent grandparents as kind of hobbling to the car on a walker."
Grandparents did flub one safety measure, however. Nearly all the kids were in car seats or seat belts, but grandparents were slightly less likely to follow recommended practices such as to include rear-facing backseat car seats for infants and no front-seats. But that didn't seem to affect injury rates.
Overall, 1.05 percent of kids were injured when riding with parents, versus 0.70 percent of those riding with grandparents, or a 33 percent lower risk. The difference was even more pronounced - 50 percent - when the researchers took into account other things that could influence injury rates, including not using car seats, and older-model cars.
What kinds of injuries did the research cover? Concussions and other head injuries, and broken bones - similar injuries regardless of who was driving.
The study does not include data on deaths, but Henretig said there were very few.
The National Highway Traffic Safety Administration has more on keeping kids safe in cars.