CAFE is particularly interesting because the government recognizes that the standard results in lighter, deadlier cars, killing thousands of additional people on American roads.
Lighter <> Deadlier
For one thing, lighter frequently means "more agile", i.e., better able to avoid a crash.
But even given a crash, modern engineering can yield great safety with light weight. See the results of a "Crash Test 1959 Chevrolet Bel Air VS. 2009 Chevrolet Malibu (Frontal Offset)" [1]. In it, the dummy driver of the big iron Bel Air is pretty thoroughly killed.