Children about seven to eight years of age.
Even if they’ve met the guidelines, kids need to be mature enough for this upgrade. Ensure she can sit properly in the seat (without pushing the shoulder belt off to reach for toys). Many kids can’t do this until they’re five or six, so if she’s outgrown her harnessed seat but isn’t mature enough for a booster, shop for a taller, higher-weight harnessed seat for the interim.
Read more: New car seat guidelines: The 65-pound rule>
High-back boosters support kids’ heads if they nod off and provide a better fit for the shoulder belt. The lap portion should lie flat across the hips, not the belly (which decreases the risk of internal injuries in a crash). The shoulder belt should sit across her collarbone without pinching her neck or sliding down.
Stick with the booster until she’s big enough to sit properly unassisted. You may face some resistance from your child if she starts to feel self-conscious around kids in the carpool who are no longer using boosters. A backless booster in a favourite colour might help.
There’s more than one safe way to install a car seat. You can use the universal anchorage system (UAS), if your car has it, or a seat belt (with the addition of a locking clip if your belts don’t have a locking feature). Consult your car’s manual and the child-seat user manual to figure out which method is best. The ideal spot for a child seat is in the middle of the back seat. Once you have positioned the seat, place your knee in the middle of the seat and use your body weight to fully tighten the straps. When you’re finished, it shouldn’t budge more than an inch in any direction at the belt path.
According to Transport Canada, your child’s car seat should be replaced if it is in a vehicle that has been in a collision—it’s even an insurance requirement for some companies.
Accessories that didn’t come with your seat (such as liners, trays and comfort strap covers) might not be safe to use. Check with the car seat manufacturer first.
A version of this article appeared in our August 2014 issue with the headline “Car seat cheat sheet,” p. 24-5.