If you are driving and you see a tornado, do you get out of the car or try to drive to a safe place / outrun it? If you can see it, get out of the car! Here is a good video about exactly this point.

But are there times when you should try to drive to a shelter during a tornado warning? In almost all cases you are better off to find the best option where you are.  But even the Red Cross recommends that if you are outdoors and just can't get to a safe place:

Get into your car, buckle your seat belt, and try to drive to the closest shelter. If flying debris occurs while you are driving, pull over and park. Now you have the following options as a last resort:

1.  If you can safely get noticeably lower than then the road, get out of the car and go there.
2. If not, stay in the car with the seat belt on. Put your head down below the windows, cover up with your hands and a blanket (or whatever you have available).

It all comes down to the circumstances, trying to stay as calm as humanly possible; and most important , common sense.  If you can see the tornado, it's too late to drive anywhere, find the best option
right now!