Mr. Newell, the former police officer, knows well that Hollywood’s penchant for making vehicle fires into dramatic disasters is unrealistic – particularly the cliché of gas tanks blowing up at the slightest provocation. Contrary to popular belief (and the fireballs that are a staple of television thrillers), he says, a tank full of gasoline does not have much room for the oxygen necessary to support combustion. “Cars only explode in midair on ‘The A Team,'” he said.