The smallest cars on the road carry the biggest risk of injury, a new report claims.  

The Insurance Institute for Highway Safety says only one of eleven small cars passed the organization's toughest test.  

The Chevrolet Spark is the only car that got an "acceptable" rating in the report out today.  

Six models scored "poor" ratings and the others were rated "marginal."  

The test involves a car hitting a barrier with the front driver's side corner at 40 miles an hour, to simulate hitting a tree or pole, or clipping another car head-on.