Usually, you want to stay in the vehicle. It protects you from lightning and any wind blown debris. Tune the radio to a local station for weather updates. If visibility is bad, turn on your headlights and slow down, or pull over in a safe spot. DON'T drive through any flooded areas.
The only time you would want to consider leaving the vehicle would be in the event of a tornado. In that case, seek shelter in an appropriate building. If that isn't possible, lay flat in a ditch. Seeking shelter under a highway overpass during a tornado isn't recommended, as they tend to act as wind tunnels.
The only time you would want to consider leaving the vehicle would be in the event of a tornado. In that case, seek shelter in an appropriate building. If that isn't possible, lay flat in a ditch. Seeking shelter under a highway overpass during a tornado isn't recommended, as they tend to act as wind tunnels.