Unless you have an armored F250, I guarantee you the walls of any room in your house are far safer. Bathroom or closet would be great. If you have to head somewhere else, that's perfectly fine, but don't leave the city. When my family lived in our smaller place, we didn't have a basement, so a couple of times we went to my uncle's grocery store and clambered into the freezer with whatever employees and patrons were already there. It was just up the road. If that is safer than your house, then do that, but telling people to head for the highway was the dumbest thing he could have possibly said, and as bad as rush hour around OKC was when I was there a week or so before, I don't even want to imagine what it was like when people were literally fleeing southbound in the northbound lanes.
I don't know where you're at, Tr, but even a trailer is safer than a car, and trailers are *not* safe. Your car might be able to outrun the storm itself, but it won't outrun RFD or an inflow unless it's designed to, and no commercial car has those features.