When installing a child safety seat or placing their infant in it, an alarming 93 percent of families made at least one error that put their child at increased risk of injury in a crash, according to a study reported in October 2014. That study, which involved 267 families, was conducted by the Oregon Health and Science University Hospital.

It’s scary enough that few people know how to use their infant safety seats correctly. But what really gives me pause is recent evidence that most folks think they know. Ninety percent of 4,167 drivers interviewed in the summer of 2011 said they were “confident” or “very confident” that their child restraint systems were installed correctly and their kids were seated correctly. 

Unfortunately, people who are sure they’re doing something right are unlikely to seek out information about how to really do it properly.

The 2011 National Child Restraint Special Use Study was conducted at 24 randomly selected locations around the country. Of those interviewed, 20 percent said they didn’t read any instructions on how to install their car seat.

Okay, I admit it: I’m the guy who didn’t bother with the directions when assembling a knockdown bookcase only to discover I should have put the back on before the shelves. Still, I was risking only a little time and frustration. Don’t risk the life of your kids. Read that owners’ manual carefully before you install the seat the first time.

Five mistakes to avoid

As part of the National Child Restraint Special Use Study, certified child passenger safety technicians inspected how drivers were using the car seats. Here are the five significant mistakes the technicians observed most often. Hopefully none will ring an alarm bell for you.

1. Using the wrong harness slot. For rear-facing seats, it’s best to use the harness slot at or below the child’s shoulders. For a front-facing seat you should use the slot at or above the shoulders. Inspectors found people using slots more than 2 inches too high or too low. Using the wrong slot may increase the risk of what the experts call “excessive excursion.” In other words, your child could be injured in a crash because he was propelled too far forward within the seat.

2. Putting the harness retainer/chest clip in the wrong position. The chest/retainer clip should be positioned at armpit level, but inspectors found it being used over the abdomen or not at all. This also can increase the risk of excessive excursion.

3. Installing the seat too loosely. The seat should not move more than 1 inch from side to side or front to back when checked at the belt path. Often in the cars inspected, the seat could be moved more than 2 inches. The danger here is that the seat itself could be propelled too far forward in a crash. (I’ve found that a good way to get a tight installation is to put your knee on the vehicle seat to depress it while you tighten the belt.)

4. Making the harness strap too loose. There should be no slack if you pinch the strap at your child’s shoulder. Inspectors often found more than 2 inches of slack using that pinch test. A loose strap could cause excessive excusion in a crash. It could even cause your child to be ejected from the seat.

5. Placing the lap belt in the wrong spot. When a child is in a booster seat or even when he or she is big enough to use the car’s seat belt alone, the lap belt should lie snuggly across the upper thighs and not on the stomach. The shoulder belt should lie across the shoulder and not the neck or face.

Get it checked

The fact that so many child safety seats are used incorrectly is less surprising when you consider that the proper methods vary with the type and model of the seat, not to mention the model of your car. So in addition to reading the car seat manual, check the owner’s manual of your vehicle. SaferCar.gov has really helpful instructions with videos showing installation of each type of car seat.

After all that, even if you are “highly confident” you got the installation right, get it checked by a certified child passenger safety technician. Many police departments have a certified tech. To find one in your area, go to the government’s Child Care Seat Inspection Station Locator.

David Schiff is a freelance editor and writer who specializes in home safety, home improvement, woodworking, child safety and music.

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