Hate to be the johnny know it all guy, but next time leave everything where it is. If that guy goes to meet his maker, the measurements taken by chp or police could prove to be invaluable in court in case his family or someone sues the city saying it was there fault.
Glad the dude is okay and way to be the good samaritan, but be careful helping people at those scenes. The state court ruled last year you can be sued for any injuries caused by moving the victim.
I gotta say.... we'd do it again if we had a replay of that day. I think that just sitting and watching someone dying (or in this case, wedged underneath a car with the driver stuck inside) is just selfish. Yeah I know, we gotta take care of ourselves, but if I was too worried about getting sued to help someone in danger then something's wrong with me.