Sigmon Put L.A. Drivers on the Alert


The “lyrics” are music to few people’s ears, but drive-time commuters certainly perk theirs up at the term “SigAlert” on the radio.

The expression is named for Loyd C. Sigmon, who joined Los Angeles radio station KMPC-AM in 1941 as an engineer and eventually became a partner with Gene Autry in its parent company, Golden West Broadcasting.

Born to a Stigler, Okla., cattle rancher, Sigmon was always interested in electronics, getting his ham radio license (and his nickname “Sig” onto the airwaves) at age 14.


Expanding on technology he used in the U.S. Army while monitoring German radio during World War II, Sigmon developed a receiver-tape recorder for KMPC to which police dispatchers could automatically send a message advising listeners of serious emergencies.

Then-Los Angeles Police Chief William H. Parker gave the project his OK but insisted that it be made available to any interested station. Although KMPC lost its exclusivity, Parker called the system “SigAlert,” ensuring Sigmon eternal membership in Southern California lexicography.

The first SigAlert was broadcast in 1955 during Labor Day weekend when a train derailed near Union Station in downtown Los Angeles. An even bigger traffic jam ensued when scores of doctors and nurses responded to the call for medical help.

And before communications theorists ever used the term “global village,” police transmitted a SigAlert to find the parents of a 15-year-old injured in a traffic accident. Minutes after the broadcast, a listener in Oregon who recognized the name called the boy’s grandmother in Idaho, who in turn notified his mother in Los Angeles.

SigAlert has now evolved into a special notice of any condition that will close traffic lanes for more than 30 minutes.

Sigmon, 88, who has lived in Sherman Oaks since 1946, no longer spends time with his ham radio but says he still stays in touch with traffic conditions via a police scanner.