About 30 million motorists age 65 and older are licensed to drive in the United States. Generally, they're some of the safest drivers on the road, rarely tailgating or speeding.
However, senior drivers are more likely to be involved in certain types of accidents than other motorists, according to the Insurance Institute for Highway Safety. They also have the second highest rate for deadly crashes among all age groups.
Here are the five most dangerous driving situations for seniors -- and how to stay safe when encountering these situations.
The 5 most dangerous situations for old drivers
Russ Rader, a spokesman for the Insurance Institute for Highway Safety, says the most common error made among senior drivers is failing to yield the right-of-way. Drivers 70 to 79 are likely able to see another vehicle but misjudge whether there's time to merge into a lane. Drivers 80 and older, meanwhile, mostly fail to see the other vehicle.
Dr. Stacey Weiland, an internist in York, Pa., says stiff joints may make it more difficult for senior drivers to turn their heads to check for vehicles while changing lanes or merging into traffic.
Staying safe: "Installing a fish-eye mirror on your side mirrors can increase your field of vision," says Walter Meyer, a traffic school instructor in San Diego.
2. Heading into intersections.
The majority of accidents involving senior drivers happen at intersections with stop signs or traffic lights, says Jason Ratcliff, a sheriff's deputy in Williamsport, Ohio. He says many older drivers either don't see the light change or don't notice the traffic signs -- or they can't stop in time because of slow reflexes.
Staying safe: Ratcliff says the best way for senior drivers to stay safe in or near intersections is to scan the scene. He recommends that drivers survey both sides of the road with their eyes -- not by turning their heads -- when approaching intersections, private drives and retail stores to look for cars and pedestrians.
"Make sure to tilt your view up a little to look for changing stoplights, instead of looking straight ahead at the car in front of you," Ratcliff says.
3. Making left turns.
Statistically, the average motorist could drive 1 billion miles -- the distance from Earth to Jupiter and back -- before getting into an accident that involves a right-hand turn, according to the U.S. Department of Transportation.
"That's because right-hand turns generally don't require the driver to pay attention to as many things as left turns," Ratcliff says.
When turning left, drivers need to look for vehicles, pedestrians, animals and other obstacles in the road in both directions, which means they also have to judge whether it's safe to turn from two directions.
Ratcliff says left-turn accidents commonly result in one of the drivers being "T-boned," or hit in the middle of the car's passenger side, by an oncoming car.
Staying safe: One way to stay safe is to adopt Michigan's "no left turn" approach to driving. The state prohibits left turns on many of its roads, instead requiring the driver to make a right at the intersection and then make a U-turn at a designated point down the road. According to the Michigan Department of Transportation, crash rates have decreased by 30 percent to 60 percent at intersections that have instituted the "Michigan left."
4. Driving at dusk.
Many senior drivers may know to stay off the road at night because dimly lit roads and the glare of oncoming headlights make it difficult to see. However, driving at dusk is equally dangerous.
"The limited light makes it difficult to judge distance and spot obstacles in the road," says Dr. Sandy Feldman, an ophthalmologist in San Diego.
The gray area between the light fading on the horizon and the dark pavement often makes it difficult for weakened eyes to adjust to the changes in light. Consequently, it's harder to spot cars and traffic signals, which can lead to confusion and trigger panic and poor decision-making.
Staying safe: If you can't avoid driving at dusk or at night, talk to your ophthalmologist about anti-reflective lenses, which may make it easier to see through the glare of oncoming headlights and adapt to sudden changes in light.
5. Driving below the speed limit.
Some seniors who are nervous behind the wheel want to go slower, thinking they're safer. But Meyer, the San Diego traffic school instructor, says going too slow is just as risky as speeding. That's because driving below the posted speed limit increases the possibility of getting rear-ended or becoming the target of another driver's road rage. Meyer says agitated drivers may cut off slower drivers to get around them or tailgate closely behind the slower driver, bumping up the chances of an accident.
"They may also become so enraged that they attempt to pass you and lose control," Meyer says.
Staying safe: If you're not comfortable traveling at the posted minimum speed limit, the best thing to do is get off the road.
As an alternative, don't drive during rush hour. "Run errands during the day, between 10 a.m. and 2 p.m., the time when the roads are typically the most quiet," Ratcliff says.
When do senior drivers hit the driving curve?
Weiland, the Pennsylvania doctor, says there's no "magic birthday" that marks the onset of driving difficulties among seniors.
"Everyone is different," Weiland says. "One person may begin to have reflex or vision issues at 60, while another may not experience this until age 72."
The inability to judge distances or stop quickly can impair a person's reflexes and ability to drive safely, according to Weiland.
That impairment can lead to accidents, which can easily translate into higher auto insurance premiums. Most states require insurers to offer discounts for seniors who complete approved driving courses. But those who rack up accidents on their driving records could see their low rates skyrocket.
"Incurring traffic tickets or filing claims for accidents, even if they're fender-benders, can raise premiums or lead to the policy not being renewed," says Brian Kane, owner of Donnelly & Sproul Inc., an insurance agency in Glen Rock, N.J.