How to Avoid Common Car Seat Installation Mistakes

Don’t allow more than 1 inch of movement either forward and back and side to side when force is applied at the belt path.

Do: Regardless of whether you’re using LATCH anchors or the vehicle’s seat belt, the installation should have less than 1 inch of movement forward and back and side to side when pulled at the belt path. If you’re installing it with the vehicle seat belt, be sure to consult your owner’s manual to learn how to properly lock the seat belt.

Don’t set the recline angle for rear-facing car seats incorrectly.

Do: Be sure to follow the manufacturer’s instructions for setting the recline on your rear-facing seat. A seat that’s too upright can cause an infant’s head to fall forward and obstruct his or her breathing. Reclining too far can reduce the seat’s ability to protect the child in a crash.

Don’t use a forward-facing belt path for a rear-facing orientation or a rear-facing belt path for a forward-facing orientation.

Do: Consult your car seat manual and the seat’s labels to make sure you’re using the correct belt path. Confusing the paths could mean the seat isn’t secure or may not work as it should during a crash.

Don’t forget to use a top tether for forward-facing installation.

Do: For a forward-facing installation, always attach the top tether whether the seat is installed using the lower anchors or a seat belt. The top tether significantly reduces a seat’s forward motion, which can reduce injury to a child, especially a head injury. Research on car seat misuse by the University of Michigan Transportation Research Institute also suggests that to some degree, a top tether use may help mitigate the effects of other misuses, such as loose harnessing or loose installation. Top tethers not only enhance safety but are also easy to use.

Don’t leave a loose harness that allows too much movement.  

Do: Make the harness snug enough so that you can’t pinch any webbing between your fingers at your child’s shoulders. A loose harness can cause your child to move outside the protection of the child seat during a crash.

Don’t position the harness at the wrong height for a rear-facing installation.

Do: For rear-facing seats, the harness should be positioned at or slightly below the shoulders. Correct harness positioning optimizes the seat’s ability to protect in a crash.

Don’t position the harness at the wrong height for a forward-facing installation.

Do: For forward-facing seats, the harness should be adjusted to fit at or slightly above the shoulders. Correct harness positioning optimizes the seat’s ability to protect in a crash.

Don’t position the chest clip too high or too low.

Do: Position the chest clip at armpit level. It’s intended to keep the harness in the proper position in the event of a crash.

Don’t use nonapproved covers and cushions.

Do: Use only covers and cushions that have been approved by the car seat manufacturer for use with that seat. These items have been crash-tested with your seat to meet compliance standards. As a rule, don’t place additional padding between the seat and your child or between your child and the harness straps.

The NHTSA study also found that the most common misuse of booster installations was placing the lap belt high on the belly or rib cage rather than low across the hips and upper thighs. If you have a booster seat, check our car seat buying guide for more information on how to properly secure your child in it and how to decide whether your child is ready for a vehicle’s seat belt alone.