I don't see how they could be as safe. This picture really makes me question that. This happened at a local track and this car had a bolt in roll bar. Granted it was a pretty extreme wreck but the cage pushed through the floor and you can see it sticking up in front of the rear tires. Thankfully nobody was hurt in this but it wasn't because of the roll bar.



Here is more pics of the wreck.

http://jalopnik.com/5390934/mustang-cover-boy-tries-to-corner-flips-over-tire-wall