Back when the earth was still flat, child safety in cars seemed to consist primarily of teaching them not to open the door on the highway.

Now things are much different, of course, but a large number of people still aren’t sure exactly how to use child safety seats, or even why they should. If you’ve ever said, “My family just put everybody in the back seat, and nothing ever happened,” then you need to keep reading.

The rate of child fatalities and injuries in vehicles has consistently dropped over the years, and it’s not because drivers are getting better. Vehicle safety improvements play a part, but putting children in appropriate seats is a major factor.

Even so, what you believe is “appropriate” may not necessarily be so, as companies have changed some of their recommendations for when children should be advancing to the next style of seat.

There are three main types of child seats: rearward-facing, forward-facing, and booster seats. The federal government sets safety standards for the seats themselves, but its up to the provinces to set laws for their use, including the child’s age and weight for each one.

Rearward-facing seats are often legislated to 20 to 22 pounds, or a minimum age of one year, before the child moves up to forward-facing, but that isn’t always the best idea. Seat manufacturer Britax, for example, recommends that a child stay rear-facing as long as possible, according to Barbara Baines, the company’s child passenger safety advocate.

“It’s a safer way to travel, because during a frontal collision, the force of the collision is absorbed through the back of the seat,” she says. “There is no energy or force being put on the weaker front parts of the body.”

Some parents believe that forward-facing seats should be used as early as possible, because the forces in a collision will often push a rearward-facing version into the backrest of the vehicle’s seat. While this does happen, the rearward-facing seat is still preferable, because the rear of the seat absorbs much of the crash energy.

In a forward-facing seat, the child’s head will shift forward and then back, putting potentially harmful force on the neck.

For this reason, rather than use weight or age measurements, parents should only move the child to a forward-facing seat when he or she has developed sufficiently to be able to walk without assistance. This is especially important because many young children are bigger than they were in the past, and may reach the weight recommendations before they’ve matured enough to safely make the switch.

“Babies that are larger won’t always have the muscle strength, even though they passed 22 pounds long ago,” Baines says. “walking unassisted indicates that they have the muscle development to hold their bodies and spines upright.”

A booster seat, meanwhile, serves only one purpose: to raise a child high enough so that he or she can use the vehicle’s seat belt. When the child is in the booster seat, his position and that of the seat belt must be the same as if an adult were sitting there: the child’s back must be flat against the back of the seat, the knees should be completely bent over the front of the seat cushion, the belt must cross the shoulder and lie flat against the middle of the chest, and the lap portion must be over the hips, not the abdomen.

As well, the child’s ears should be in line with the middle of the head restraint. If any of these positions aren’t met, it’s back into the forward-facing seat with five-point harness.

You already know that child seats shouldn’t be placed in the front seat, especially rearward-facing ones, because airbags deploy at some 300 km/h out of the dash. Ideally, children should always ride in the rear seat, and if they can’t, such as in two-seater cars or pickup trucks, the frontal airbag must be disabled.

Getting the child seat property installed in the vehicle can be an issue, since they aren’t always easy to put in. Estimates of improperly installed child seats reach as high as 80 percent or more.

Every new vehicle sold in Canada manufactured on or after September 1, 2002 has a Universal Anchorage System, or UAS. It’s also known as LATCH, for Lower Anchors and Tethers for Children. Child seats can be installed using the UAS or the vehicle’s seat belt (one or the other, but not both at the same time) but if you have an older vehicle that doesn’t have shoulder belts in the rear seats, you’ll have to get them installed before you can transport your child.

If that isn’t possible, then the car isn’t suitable for carrying youngsters who still require child restraints.

How do you know if your car seat is properly installed? First, follow the directions that came with the seat, and also with your vehicle’s owner’s manual.

Then, try to attend a car seat clinic in your area. Ensure that the people hosting the event are certified for child seat installation, such as through programs from St. John’s Ambulance or the Child Passenger Safety Association of Canada.

“You don’t just want anybody doing it,” Barbara Baines says. “Even the majority of police are not trained. You need someone who’s taken a course in how to do it.”

And just as your car may be too old to carry young children safely, a child seat may be as well. Although its not required by legislation, Transport Canada says that all child and booster seats sold in this country have an expiry date, or “useful life” date on them.

The main reason is that older seats may not meet updated safety standards, but if the seat is old enough, the plastic and harness webbing could become brittle, especially if the seat has been exposed to extreme heat, cold, or sunlight for an extended period of time. Transport Canada has a list of several brands and the years that can be considered each one’s useful life.

If you have a seat that was made before January 1, 2012, you can use it for your child until it reaches its recommended limit, but legislation by Health

Canada’s Consumer Product Safety Act makes it illegal for you to advertise it, sell it, or give it away, unless it meets the new safety standards that were brought in on the first of the year.

And while this isn’t legislated, it’s recommended that you replace any child seat that has been involved in a collision, even if there wasn’t a child in it at the time.

Any time you buy a seat, whether one that’s new or a used one within the acceptable time limits, be sure you register it with the seat manufacturer. Child restraints can be subject to recalls just as cars are, and if you’re registered, you’ll get notices in the mail. You can also visit Transport Canada’s database for information on car seat recalls and notices.

And while there are government standards for seats, Baines reminds parents that they are minimal. Just as with cars, some seats are better than others when it comes to safety.

Baines suggests looking for a seat that has additional energy-absorbing foam on the sides and head areas of the restraint, a harness system that can be moved without having to be rethreaded through the seat back, and “wings” that curve around the child’s head to hold it steady, especially in the event of a side-impact collision.

When you’re hauling precious cargo, you want every advantage you can get.