As many of us prepare to head over the river and through the woods to grandmother’s house for the holidays, car seat safety has to be a top priority.

But a lot of Western New York families are making major mistakes, putting their little ones at risk.

Child Passenger Safety Technicians with Catholic Health tell News 4 as many as 9 out of 10 car seats being checked at car seat safety events are installed improperly or being used incorrectly.

“That’s really scary when we consider the leading cause of death for kids and infants in the United States is motor vehicle collisions,” said Christina Lewis, the manager of clinical education for women’s services for Catholic Health, who also teaches child passenger safety technician courses.

Lewis says, in Western New York, puffy coats and buntings are big problems.

“Because most coats on the market are very fluffy, they have lots of extra insulation to keep kids good and warm, and hold the harness too far away from the body,” Lewis explained.

In a crash, the consequences of that could be devastating.

“If they’re rear facing, they could actually slide all the way out of the seat and be thrown through the vehicle,” Lewis said, adding that children who are sitting in forward facing car seats can also be thrown forward, hitting their heads on the seat in front of them.

“Shaken baby injuries are so common in crashes if that harness isn’t tight,” she said.

The experts say your best bet is to use a coat that’s specifically designed to be used with a car seat, like this one. These kinds of coats allow you to remove the puffy layer from the front, so the harness sits snuggly against your child.

You can also remove your child’s coat before buckling him or her into their seat, then use the coat as a blanket on top to keep them warm. Lewis advises dressing your kids in layers for their comfort.

That said, the coat problem is only part of the problem if your car seat is not installed properly in the first place.

Catholic Health offers free car seat classes to help make sure families are using the correct seats for their child’s age and size, to make sure the seats are installed correctly.

“A lot of the errors we see are that people are not locking their seatbelt off,” said David Lewis, a Child Passenger Safety Technician Instructor with Catholic Health. “You want to pull that shoulder harness out as far as it will go and that will usually engage a lock on your seat belt so you can lock it off, or they’re not tightening the car seat in. You want to make sure that car seat is tight.”

David Lewis also says technicians often find that children are not harnessed correctly in their seats.

“They’ll have that chest clip too low, which is dangerous because it doesn’t hold that harness where it needs to be in case of collision,” he said.

The harnesses need to be snug against a child’s body to be effective.

“You do want to have that tight enough that you cannot pinch any webbing,” David Lewis advised.

The experts also want to remind parents to be aware of car seat expiration dates. Especially with the Western New York climate, where seats are in the bitter cold then we blast our heaters when we get in our vehicles, the seats break down over time.

“Six to seven years and that plastic has degraded to a point where it is no longer safe,” David Lewis said, adding that different types of seats have different windows for expiration dates.

It’s clear, when it comes to car seat safety, there are a lot of things parents need to keep in mind.

To learn more about all of the classes Catholic Health offers for parents, including the car seat sessions, click here.

With five weeks to go until her son is due, News 4’s Katie Alexander turned to the pros at Catholic Health to help her install her car seat. Watch the videos below to see our full Wake Up coverage.