Driving is a powerful symbol of competence and independence — besides being a routine part of adult life. But the focused concentration and quick reaction time needed for safe driving tend to decline as you get older. Alzheimer's disease accelerates this process dramatically.

Alzheimer's robs people of their short-term memory, so they get lost easily, sometimes even in familiar territory. Losing your way, however, doesn't necessarily make you a hazard on the road.

A decline in visuospatial skills, which help drivers judge distances and predict upcoming traffic problems, seems to play a larger role in making people with Alzheimer's unsafe drivers.

Drivers with Alzheimer's may also have trouble prioritizing visual cues. An irrelevant sight, such as a dog jumping behind a fence, may distract them, so they fail to notice important cues, such as brake lights or traffic signs.

Because Alzheimer's diminishes reasoning skills, it often is up to caregivers to determine when their loved ones become unsafe behind the wheel. Some aspects of a person's day-to-day behavior can indicate whether he or she has lost the skills needed to drive safely. These include difficulties in:

• Coordination
• Judging distance and space
• Engaging in multiple tasks
• Staying alert to what's happening nearby
• Making decisions and solving problems

Warning signs of unsafe driving include:

• Forgetting how to locate familiar places
• Failing to observe traffic signals
• Making slow or poor decisions
• Driving at an inappropriate speed
• Becoming angry and confused while driving

Opinions vary on whether driving should be allowed at all after an Alzheimer's diagnosis. For some people, it may be easier to give up the wheel early on, when they can still grasp the potential hazards. On the other hand, people in the early stages of the disease may be able to safely limit their driving to short daytime trips in familiar surroundings. Either way, they should stop driving:

• At nighttime, dusk or dawn
• During rain, fog, snow, ice or glare
• On highways or at high speeds
• During rush hours or on long trips

Even if your loved one willingly gives up driving at first, it may become an issue later on, as his or her understanding of the risks diminishes. Here are some strategies for keeping your loved one out of the driver's seat.

• Get a note from the doctor. Sometimes it helps if an authority figure — physician, lawyer, insurance agent — tells your loved one to stop driving. Having something in writing can be a useful reminder.
• Control access to the car and keys. In many cases, it's a simple matter of "Out of sight, out of mind." Parking the car around the corner may be enough. Some caregivers sell the family car and buy one that's a different color so that the person with Alzheimer's thinks it belongs to the neighbors. If your loved one insists on carrying a set of car keys, you can replace them with keys that don't work.
• Disable the car. Removing a battery cable will prevent the car from starting. Or a mechanic can install a "kill switch" that must be engaged before the car can start.
• Ease the transition. Arrange for alternative transportation, perhaps via the city bus service or a senior van route. You may be able to establish a payment account with a taxi service so that your loved one won't have to handle money. Many items, such as groceries, meals and prescriptions, can be delivered. Some barbers and hairdressers make house calls.

Whether your loved one stops driving all at once or in stages, he or she will probably grieve this loss of independence. Be as patient as you can throughout this process, but remember to stand firm. Arguments and explanations rarely make it easier to accept.

What will help is to keep routines as normal as possible despite the prohibition on driving. Arrange for family and friends to visit regularly and to take your loved one out to run errands. When you're together, focus on activities your loved one can still do and enjoy.