Older drivers are the safest drivers, hands down. But many have been driving so long they've forgotten some of the rules, or haven't changed their driving habits to account for reflexes dulled by age. Safety experts and state regulators feel so strongly about the benefits of classroom refresher courses -- even for those who've never had an accident or racked up a single ticket -- that a majority of states require insurance companies to offer discounts. Even in states where a discount isn't the law, most companies offer a break for defensive driving courses anyway. The AARP Smart Driver Course, launched in 1979 as "55 Alive," is the largest and most well-known defensive driving course for those of a certain card-carrying age. Last year, more than 560,000 people took it, either online or in a class held at a senior center, car dealership, library or other community space. Most get car insurance discounts in exchange, helpful because car insurance rates start to rise once driver reach 70 or so. The class is four to eight hours long, depending on the state, and includes no tests, either on the road or at a desk. What it does include is a good deal of discussion about aging's effect on seeing, hearing and reacting, and tools to compensate. It reviews road rules most of us haven't visited since high school. And it appears to work. An independent study by the Eastern Virginia Medical School showed course participants made fewer hazardous errors than non-participants and were better able to regulate their driving behavior, scheduling around night-time driving, for example, or altering routes to avoid high-speed traffic or tricky intersections. "A lot of people do hang up their keys early because they've lost their confidence behind the wheel. Our course allows them to get that confidence back up," says Julie Lee, vice president and national director of AARP Driver Safety. "This is about keeping people on the road. We want people to be mobile as long as possible, and we want them to be safe."