Children's car seat restraints are impact sled tested to evaluate and thereby "rate" their safety qualities.To determine whether these restraints are serving their primary purpose of protecting the child in impact situations,it is necessary to test in two ways those restraints that require a top-tether strap. These restraints should be tested: 1) installed in accordance with the manufacturer's directions; and 2) installed in the manner they are frequently being used.In this study the five children's car seat restraints top-rated by a leading consumer organiza- tion were impact sled tested properly installed on the sled with a top-tether strap in use as required.The same five restraints were then tested improperly installed without the top-tether strap, secured only by the auto lap belt.A survey conducted by the Insurance Institute for Highway Safety shows this is the way such restraints are often being used. In addition, two leading restraints not requiring a top-tether strap, but secured by the auto lap belt,were also impact sled tested.This study shows that the five toptether strap restraints, when properly installed with the top-tether strap and lap belt, and the two restraints not requiring a top-tether strap but secured by the auto lap belt only, give good protection to the child in a frontal crash.It also shows that, with one possible exception, the five restraints that require a top-tether strap do not provide adequate protection to the child if the top-tether strap is not installed.