http://www.iihs.org/research/topics/pdf/r1098.pdf

It's one of those "no duh" things, but they finally correlated roof strengths of various SUVs with their corresponding rollover death and injury rates.

Russ Rader, IIHS Communications

Automakers often argue that roof strength has very little or nothing to do with deaths in rollovers. The IIHS has taken them to task on that assumption, releasing a study that establishes a clear link between strong roofs and lower death and injury rates in rollovers. The Institute looked at a group of SUVs, measured the strength of their roofs with the same method used by the government, and then correlated death and injury rates in those SUVs in rollover crashes. The study found that the strongest roofs are associated with injury risks 39 to 57 percent lower than the weakest roofs. All of the SUVs in the study group met the current federal standard, but some were nearly twice as strong as the government requires.

The strongest roof was on the 2000-04 Nissan Xterra while one of the weakest was on the 1999-2004 Jeep Grand Cherokee. Within 5 inches of crush, the Jeep withstood a force as high as 6,560 pounds, which amounts to 1.64 times the weight of the 4-wheel-drive version. The corresponding figure for the Xterra was 11,996 pounds.

After both vehicles were subjected to 10,000 lbs of crushing force... the 2000 Xterra's roof was crushed about 2 inches; the 2000 Explorer's was crushed about 10 inches. It certainly brings back memories of the whole Firestone/Explorer fiasco..

Here's a chart of the NHTSA results:

The strongest roof tested is the XC90's, while the strongest relative to vehicle weight is the Jetta's.

you know what this means for future vehicle weights...