Most parents are aware that they should strap in their precious cargo into car seats, but many fail to properly install them.

Certified car seat installation technician Maureen Dennis says as many as 80 per cent of parents are improperly installing car seats. In her blog, Weewelcome, she explains the five most "deadly" car seat installation mistakes.

1. Wrong seat at the wrong age: Dennis says a mistake parents often make is using a car seat that’s not appropriate for their child’s height and weight. She says this usually happens when a parent rushes to get their child into the next car-seat stage. A common example is moving a child into a booster seat when a forward-facing one still fits. According to Transport Canada, a child must weigh at least 40 lbs and meet a booster seat's height guidelines before it is safe for parents to make the switch from a forward-facing car seat.

"You need to check your car seat manual," Dennis told CTV's Canada AM on Tuesday.

There are three car seat stages before children can sit in a vehicle wearing just a seat belt: rear-facing, forward-facing and the booster seat stage. For a detailed explanation of what type of seats are appropriate, visit the Transport Canada website.

2. Car seat not securely installed: Denis, who is also a parent, says car seats are often not secured tightly enough to a vehicle.

"(Car seats) should not move more than an inch either way."

3. Harness too loose: Another common car seat installation mistake is leaving the harness too loose. A simple solution she says is to conduct a harness "pinch test" at a child's shoulder. "You shouldn’t be able to pinch anything."

4. Placing the chest clip: Improper placement of a car seat’s chest clip is another mistake some parents make. She says the clip should always be at the armpit level. "Not too low, such as down near their belly button, or up to close, near the neck," she explains on her blog.

5. Improper placement: Even if a car seat is installed and secured correctly, Dennis says improper placement of a car seat can also put your child in danger. She says rear-facing seats should be positioned at a 45 degree angle, and forward-facing seats need anchored to the car using a tether strap.

Dennis says according to a report from the Canadian Paediatric Society, a correctly installed car seat can reduce the risk of fatal injury by 71 per cent, and the risk of serious injury by 67 per cent.

The parenting expert will be hosting a number of free car seat installation workshops in Toronto and Vancouver. Check Denis' blog for more information.