I don't know about that. Felipe Massa was nearly killed by that spring that come of Barichello's car earlier in the year. I would say that Nascar is safer now that they have the new car. However, I would definitely say that Indycar is the most dangerous...going 220+ on an oval in an open wheel car is going to be dangerous no matter what safety features the car has.
Nascar markets their crashes, it's in almost every commerical, and there is like a serious crash ever race, if nor more, I don't know about their breaks, but I know they use a adequated fueling sytem in the pits...everything in Nascar seems ro be geared toward Entertainment 1st, car, driver-2nd. I mean they made a. If fuss over the new car. There wasn't much fuss over the Kers system in F1, or went from turbo engines to naturally aspirated. Only whinning came when Ferrari and others threaten to leave.
Open wheel racing is dangerous, because of the high speeds and the lack of physically "whole" car.