I know how stressful it can be to worry about a loved one who doesn't live close enough to visit as often as you'd like. Hopefully you have a family
Just getting the topic on the table is a good start. She was involved in a recent crash, and that's a big warning sign. Find out more about the circumstances of the accident to see if it suggests any problems with vision, thinking, or moving—the three key functions needed to drive safely. For example, did it involve her making a left turn? That might indicate problems with depth perception and judging the speed of oncoming traffic.
The next time you visit your mother, be sure to walk around the car to see if there are accumulating dents, scratches, and dings. Go for a ride when your mother drives to get a sense of how she's doing. We can all benefit from a refresher driving course. See if she's willing to take a driving class for seniors. This will earn her a discount on her auto insurance and provide tips on how to drive well despite slower reaction times. For more ideas, see Resources for Tuning Up Driving Skills.
Another great idea is to get a driving assessment from a certified driving rehabilitation specialist. These specialists assess the driving skills of older drivers and offer training to improve them when possible.
tradition of open, honest, and frequent communication. I'd recommend asking your mom how her driving is going. Has she encountered any recent problems?