Only half of all hybrid vehicles on the U.S. market are …

Only half of all hybrid vehicles on the U.S. market are more fuel-efficient than their non-hybrid versions, researchers at the Union of Concerned Scientists find: some models pair a big gas-guzzling engine with hybrid technology in a way that enhances only performance, not fuel economy, explains UCS’s David Friedman. Newsweek
April 14, 2008