When deciding it is time to take the car keys away from an elderly driver, a caregiver must balance the desire to keep a loved one safe with their desire to stay independent.

Are elderly drivers really a hazard? Or does their experience make them safer drivers? When should a caregiver think about pulling the keys?

Researchers from Australian National University set out to examine the effect of aging on driving performance by having elderly subjects take a 12-mile on-road driving test. The participants were monitored by a literal "back seat driver" who noted the number of so-called ‘critical mistakes' made, including tailgating, neglecting to check blind spots and speeding.

The results: Those who were between the ages of 70 and 74 only made one serious driving error, while those 85 or older made an average of four mistakes.

According to the National Highway Traffic Safety Administration (NHTSA) monthly newsletter "Safety in Numbers," the NHTSA cited the top five types of accident-inducing maneuvers a senior driver is most likely to make: changing lanes on a road with at least four different lanes, making a left turn at an intersection when there is no specific turn arrow, merging onto a highway via a ramp with a yield sign, making a left turn at an intersection containing a stop sign, and merging with traffic that is going 40-45 miles per hour by making a right turn at a yield sign.

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These sources both point to the validity of caregiver concerns. If you've noticed changes in an elderly loved one's driving abilities, it may be time to devise a plan for taking away the keys.

Read: Taking the Keys: What To Do if Mom or Dad Won't Stop Driving