Many U.S. states are making it easier for elderly drivers to stay on the road, despite the fact that they are more likely than any other group except for 16-year-olds to be in car accidents, according to a study released Saturday.

"It appears that automobiles are inspected with much greater scrutiny than the drivers of those automobiles," Robert Fields and Gale Valtinson said in a paper presented to a meeting of the American Psychological Association."Even when drivers are tested for impairment, the methods used by most states to identify impairments are variable and not good at predicting poor drivers."

The National Highway Traffic Safety Administration reports that since 1985, drivers over 60 have increased by almost 50 percent in the United States.

While most are safe drivers, those with cognitive impairments such as Alzheimer's disease and those over 80 represent sharply increased risk of accidents, the study said.