Illinois is the lone state in the country that requires older drivers to have their skills behind the wheel tested more frequently than younger drivers, and an insurance industry report out Monday says it has reduced the number of elderly drivers and the volume of crash claims from them.

The Highway Loss Data Institute, a part of the Insurance Institute for Highway Safety, said that the more frequent testing in Illinois has culled drivers most at risk for crashes from the driving ranks.

“The unique mix of regulations in Illinois appears to reduce crash risk,” said Institute Vice President Matt Moore, “and it seems to do that by getting the riskiest folks off the road.”

Statistics show that older drivers are more crash prone than drivers in their middle years, but the youngest drivers have more crashes than any of their elders. Illinois requires drivers over 75 to renew their licenses every four years and to pass a road test with each renewal. Those above age 80 face renewal every two years, and those 87 or older are tested annually.

Though data in the HLDI report showed positive results in Illinois, a similar law in New Hampshire was deemed ineffective and was dropped from the books six years ago. Since then New Hampshire has required all drivers to renew their licenses every five years.

In evaluating the Illinois law, HLDI analysts looked at the elderly crash rate in four bordering states — Indiana, Iowa, Missouri and Wisconsin. All five of the states require older drivers to renew in person and prove their vision remains adequate. Renewal cycles varied by state and age group, but those in Illinois were on the more stringent side.

In comparing Illinois’s crash claim rates with those of the neighboring states, the analysts found that claims for vehicle damage and bodily injury to people in other vehicles, as well as pedestrians and bicyclists, was lower in Illinois than would have been expected for drivers 75 and older.

The HLDI analysts compared crash rates in New Hampshire with those of adjoining Vermont and Maine, but during the period when the law requiring more frequent testing of the elderly and after it was repealed.  They determined that New Hampshire had higher-than-expected claim rates for vehicle damage and bodily injury, and a slightly lower claim rate under medical payment coverage.

“Crash risk in Illinois, with its special licensing requirements, is lower than in the control states, but New Hampshire is sort of a cautionary tale,” Moore says. “Unless there are transportation alternatives [like public transit] for older folks, we may not see the same benefits Illinois has seen.”