Why are announcements of traffic problems called “Sigalerts”?
They are so-named in honor of their inventor, Loyd C. Sigmon, who died in June 2004 at the age of 95. Sigmon devised his traffic alert system in 1955 when he was a co-owner of radio station KMPC and looking for ways to boost its listening audience. When the system debuted, it covered all sorts of emergencies, not just traffic tie-ups. On Labor Day 1955, the first SigAlert was broadcast by six radio stations for a train wreck near Union Station. Other early bulletins included warnings of rabid dogs, a collapsing dam and a ship collision in Los Angeles Harbor. Today, a SigAlert is issued only when one or more lanes of traffic will be blocked for at least half an hour. The term has become so familiar that it was added to the Oxford English Dictionary. Sigmon based his system on technology used during World War II to monitor German radio broadcasts. He set up a system that enabled police dispatchers to transmit an inaudible radio tone that could be picked up by special SigAlert receivers i
