depending on the situation, first responders do try to put there cars/trucks in such a way, so they will act like crash barriers, when tehy respond to a car crash. Handbrake on and steering wheel full to the left or right, so if it does get hit, it will roll to the side of the road, instead of making the pile larger. Equipment is replacible, people aren't.

For normal people, always make sure you are safe. We don't need another victim. Keep you action, down to what you know and have been trained to do.