When she's not with you, walk around her car and look for signs of damage.

Everyone's car gets nicked now and then by someone else's door in a parking lot, but does her car have the kind of scratches or dents that could indicate driving mishaps? If so, ask her about them.

If you've observed some questionable driving on your mother's part, ask her whether she's gotten any tickets for speeding or other violations.

Naturally, it's best to do this in a neutral, nonaccusatory way at a time when she's not behind the wheel.

If you're not comfortable asking about tickets, ask whether her car insurance rate has gone up.

If your parent's rate has increased, this may be a sign that she's had driving infractions.

Check in with trusted friends and neighbors about her driving.

Don't wait for your parent's friends or neighbors to call you if you're worried about your parent's driving. They may feel uncomfortable approaching you with any concerns but may talk with you if you contact them directly. If you live far from your parents, try to identify one or two such people who would be willing to keep you informed about your parent's driving and other safety matters. Contact them regularly, and make sure they have your contact information as well, so they can reach you if anything comes up.