Roundabouts are circular causeways that allow traffic to flow in a four-way intersection without stop lights or signs. This new way of managing traffic is meant to save lives, but they have some older driver's heads' spinning.

AARP Drivers Safety runs a program called the AARP Smart Driver Course, which teaches drivers of all ages how to better navigate traffic. They asked 200 of their volunteer driving instructors which traffic situations were considered the most challenging for their students. Slightly more than half responded that roundabouts posed the greatest challenge to elderly drivers, while only 13 percent responded that traditional four-way stops were the toughest scenario faced by these drivers.

That flies in the face of what's actually happening on American roads: research suggests 37 percent of fatal vehicle crashes involved drivers 70 and older occur at intersections. The main causes of these crashes is failure to yield and inappropriate left turns, two problems eliminated by the use of a roundabout, according to the Insurance Institute for Highway Safety.

Roundabouts are popping up all over American roadways and for good reason; research shows they're safer for both pedestrians and motorists and alleviate traffic congestion, according to the IIHS. That being said roundabouts are still daunting to drivers of any age, says Julie Lee, Vice President and National Director, AARP Driver Safety.

"Roundabouts are still new in many parts of the country and it is common for drivers of any age to be unfamiliar with how to navigate them. The critical element in properly navigating a roundabout is to take it slow, and beware of the traffic around you," Lee said.

Older drivers are nervous when it comes to roundabouts, but they're not the worst. A two-year study on roundabouts by University of Maine civil engineer Per Garder found drivers over 70 took 3.95 seconds, on average, to navigate a roundabout. The only age group that waited longer to enter traffic were drivers under 20 at 4.85 seconds.

More than 2,200 roundabouts have been built since the first one showed up in Nevada in 1990. As the number of roundabouts have grown so, too, have the amount of elderly drivers on the road. The number of Americans over the age of 70 is set to explode in coming years, going from 28.5 million in 2011 and rising to 52.7 million in 2030, according to the U.S. Census. Roundabouts and older drivers will have to get along.

There is no comprehensive national plan on how to deal with aging drivers. The issue is mostly left to family members to hash out, and sometimes drivers end up behind the wheel long after they should have hung up the keys. Organizations like AARP offer driving coaches for older drivers. Driving rehabilitation specialists assessments are even sometimes covered by health insurance or Medicaid. The American Occupational Therapy Association provides a tool on their website for locating such specialists by zip code.