Vision
Any change in your vision should be immediately checked out by an eye specialist. Many vision changes can be halted or compensated for if discovered early enough. Check each of these:
Peripheral vision
What you see out of the corner of your eyes can diminish as part of the natural aging process, or due to eye disease. Compensate for this problem by turning your head more often to observe traffic on both sides of your car or truck.
Depth perception
Your ability to judge distances may not be quite as good as it once was. To compensate for this, leave more room between your car and the car in front of you. Use a three second rule: when the vehicle in front of you passes an object, count slowly to three and see at the end of three seconds if you pass that same object. If you pass the object sooner than three seconds, you may be following the car in front of you too closely.
Night vision
Your ability to adjust to low light conditions and to recover from the glare from the headlights of other cars may diminish because your eyes may not be able to focus as quickly, or because of the effects of medication.
Clarity
Fine detail such as the writing on road signs or the numbers on the speedometer may become more difficult to see. If you have trouble seeing the wording on road signs or details seem "fuzzy" a consultation with an eye specialist will often lead to a practical solution.
Hearing
The ability to hear sirens and horns is important, but may become more difficult as you get older. Modern cars with interiors well-isolated from road noise compound this situation. Lower the volume on the radio and check your mirrors more often to see if emergency vehicles are near.
Mobility and reaction time
Aging often affects your joints and muscles. Stiffness, pain, and loss of strength make driving more difficult, in addition to less enjoyable. Devices such as power steering, larger mirrors, and automatic transmissions may make driving easier for you.
Give yourself more time to react to other vehicles and road conditions.
Medication
Prescription drugs and medications sold over the counter, such as decongestants and cold remedies, may cause drowsiness, impair hand/eye coordination, and affect judgment. Be especially cautious when taking medicine for pain and arthritis. Alcohol often intensifies the effects of medication! Be sure to read all warning labels on the medication you take and ask your pharmacist or doctor about precautions to take before getting behind the wheel of a car.