Roughly 73 percent of child car seats aren't installed correctly, according to the National Highway Traffic Safety Administration. There's a good reason -- car seats are complicated. There are lots of decisions to make that can affect your child's safety in the event of a crash, including which seat to buy based on your child's age, height and weight and the best fit for your vehicle, where to put the seat, whether the seat should be rear- or forward-facing, and how to tighten the car seat properly, says Eileen McDonald, program director at the Johns Hopkins Children's Safety Center in Baltimore, Maryland. To make matters worse, 20 percent of parents wing it, neglecting to read any instructions on how to properly install their child restraints, according to a recent NHTSA survey, which interviewed 4,167 drivers at child restraint inspection stations across the country. Even those who do read the manual don't always get it right. Here are five of the most common car seat installation boo boos:read more