How come as people get older they tend to drive more cautiously?

a lot of reasons i suspect ---- slowing reflexes ---- an appreciation of how dangerous other drivers can be ---- eyesight less than optimal ----- slower reflexes ---- more considerate of other drivers

Sometimes they can't see as well, their reflexes are slower, and they may be less mobile in doing tthings like shoulder-checking. They also have more life experience that teaches them some drivers are idiots so you have be careful not just for you, but for them , too.