What should I have done?

So Hubby and I are at a light on our way home from dinner at Mom's tonight. I'm on his cell with a friend and this car pulls up next to us. I made a comment that the windows were really foggy in the back. The person was waiting to make a right turn. The next thing I know the person turns and totally misses the road by going over the curb into a shallow ditch. They proceeded to drive a few feet down the ditch till they stoped before a road sign.

Now there is always a cop at that intersection...except right then! And I'm talking cops who will give you a ticket for crossing your eyes while driving. They sat there for a minute before the light changed so I don't know what they did. I didn't have the number for thoes cops so I didn't call. I kinda think I should have but the person may have driven off by the time I got a number and called to report it. But then again there most likely is a very drunk person in that car. What a mess! I just don't understand what makes some people do what they do.

I've been in that situation before. I called 911 and gave the road, location, direction, vehicle type, and license plate number. I felt a little weird about calling 911, but then reminded myself that someone careening all over the road IS an emergency. Either they are drunk and likely to kill someone, or they might be sick or something and need a cop's help. (Probably drunk.)