Aluminum may be a great metal, but it isn’t a miraculous metal. In its April 13 letter, the Aluminum Association criticizes my op-ed, “Coffee Won’t Kill You, But CAFE Might” (April 5), for supposedly confusing vehicle size and weight. According to the association, it is size, not weight, that is “the leading automotive safety determinant.” Don’t be so sure. A Highway Loss Data Institute study compared hybrid cars with their non-hybrid twins, which were the same size but lighter. It found that the greater weight of the hybrids, due to their battery packs, reduced the odds of injury in a crash by 25%. That’s just one study, but it undercuts the claim that size is the single most important factor.
More important, aluminum isn’t weightless. A stringent CAFE standard can restrict the addition of aluminum crumple zones to a car just as it restricts the addition of any other material (except perhaps helium balloons). CAFE standards impose trade-offs. It would be refreshing to see CAFE’s advocates admit that simple fact.