When it was time to buy car seats for her two little boys, Kelly Zimmerman says she was willing to spend whatever it took to keep them safe. However, even after settling on fairly expensive seats, she had to resort to using a towel to make them level.
"I didn't feel comfortable with that solution though," she says. "To put a rolled towel under the seat just made me feel a little uncomfortable."
Zimmerman's not alone. A new study looking into how cars and car seats fit together suggests that solutions like these might be unsettling, but they are not at all unusual.
John Bolte, a researcher at the Ohio State University College of Medicine, has tested nearly 3,200 combinations of car seats and vehicles. He and his team are finding that back seat designs vary widely, meaning not all cars and car seats are a good fit.
"It's impossible just to sit the car seat on the car, or on the seat pan, and have it match up perfectly," Bolte says. "And so there are some things I think we could improve upon."
Bolte says that before you buy a seat, you should measure your car. Pay attention to the angle of the seat, the width and even things like built-in headrests.
"If it's a set headrest at an angle, and you have such a tall car seat, the car seat won't sit back against the back of the seat because the headrest is in the way," he says.
Experts are working with carmakers and car seat companies to encourage more compatibility. In the meantime, before you buy a car seat, ask if you can take it outside and install it to see how it fits. Once it's in, you can check with your local fire department to make sure that it's safely installed.