I'd not slap her. First, I would make sure whose ever children were in the car with her never are influenced by her ever again - whether they are hers or someone else's. That's NOT the kind of example that children need. And if she was beating up an old lady she doesn't know, chances are, she probably hits the kids, too.

I hope they checked the 19-year-old for her blood alcohol level or other "stimulants."

81 is not too old to drive if the person still can see well, and drive well. There are 61-year-olds that shouldn't be driving and 91-year-olds that are fine driving ... Great-Great Aunt Flora was furious when, at age 96, they told her she was restricted to only daytime driving because her eyesight was failing. "They" were right, but there was no telling HER that!

Back to Ms. Vasquez - no, I don't want to slap her. She'd just be expecting that, obviously. I would:

A. Yank her driver's license for ten years.
B. Sentence her to 3000 hours of community service doing something like picking up trash on the roadside.
C. Pay all that woman's medical bills - garnish any wages, sell her car, etc.
D. Find some way to give her a lesson on civility - preferably taught by someone much larger and stronger than she - as well as anger management.