His research is based on overall sales. Your quote ignores a key point made later in the article: > His research found that light trucks (which include SUVs)

His research is based on overall sales. Your quote ignores a key point made later in the article: > His research found that light trucks (which include SUVs) represented about 20 percent of passenger vehicles sold in the United States in 1980. That figure had climbed to 51 percent by 2004. In other words, cars are not getting heavier. American car buying patterns are changing. They heavy vehicles American consumers were increasingly buying over that period were the same weight they had always been.