In most parts of the world, people have little use for alcoholic breath, but the Japanese have dreamed up a way to make it stop a car. Troubled by the steady increase in the number of drunken Japanese drivers and the traffic deaths they cause (1,200 last year), a Honda Motor Co. Ltd. engineer named Kazutaka Monden has developed a puritanical gimmick called the Sniffer that shuts off a car's engine when it detects alcoholic breath.
Installed at the top of the steering column, the Sniffer consists primarily of a thumbnail-sized gas sensor. Whenever the presence of a potentially combustible gas closes...