Radio Broadcaster Put the ‘Sig’ in Traffic Alerts

Times Staff Writer

Loyd C. Sigmon, whose “SigAlert” freeway traffic jam warning system made him perhaps the most famously unknown figure in Southern California, has died. He was 95.

“People usually think it’s short for ‘signal alert,’ ” KABC traffic reporter Jorge Jarrin said Thursday on hearing of Sigmon’s death. “They’re surprised to find out it’s from a guy’s name.”

Sigmon, who died of natural causes Wednesday in an assisted living facility in Bartlesville, Okla., 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.


Five decades later, the SigAlert tops everybody’s list as one of the most distinctive aspects of L.A.’s car culture, said Matthew Roth, founding curator of the Petersen Automotive Museum and historian for the Automobile Club of Southern California.

“It’s uniquely Angeleno that this guy came up with this, broadcast it daily and it became a mark of local experience,” Roth said. “It’s the perfect summary of a large swath of daily life here.”

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. In response to the LAPD’s plea for medical help, so many doctors and nurses descended on the crash site that they created their own traffic jam.

Other early bulletins included warnings of rabid dogs, a collapsing dam and a ship collision in Los Angeles Harbor. In another case, a pharmacist who made a potentially fatal error in filling a prescription phoned police, who issued a SigAlert, which the customer heard in time to avoid disaster.

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 -- a Los Angeles Daily News sports reporter once referred to a sneeze-plagued golfer’s “Sig-alert sinuses” -- that it was added to the Oxford English Dictionary a few years ago.

Sigmon based his system on technology used during World War II to monitor German radio broadcasts. He knew about it from a wartime stint as head of noncombat radio communications for the U.S. Army in Europe.


In Los Angeles, he set up a system that enabled police dispatchers to transmit an inaudible radio tone that could be picked up by special SigAlert receivers in local radio stations. The receivers would then tape-record the dispatcher’s emergency bulletin and flash a red light and sound a buzzer to alert the radio-station engineer.

By pressing a button, the engineer could broadcast the message to listeners in a matter of seconds.

Then-Police Chief William Parker, who had approved the program for use by local radio stations, named it after Sigmon.

SigAlerts “were such attention grabbers that a lot of companies wanted to sponsor them,” Sigmon later said. “ ‘And now, so-and-so presents a SigAlert!’ But we had a rule at KMPC against that.”

In 1969, the California Highway Patrol took over the monitoring of local freeways from police and assumed responsibility for issuing SigAlerts, which became confined mostly to traffic matters.

Sigmon was born in 1909 to a Stigler, Okla., cattle rancher and became fascinated with electronics at a young age. At age 14, he got a ham radio license and first broadcast his nickname, Sig.

In 1941, after helping build a radio station in Kansas City, he joined KMPC-AM as an engineer and, after his Army hitch from 1943 to ‘46, eventually became a partner with Gene Autry in KMPC’s parent company, Golden West Broadcasting. With Autry, he also later became a part owner of the California Angels baseball team, his family said.

In addition to overseeing eight radio stations and two TV stations, he reportedly helped pioneer the helicopter traffic watch in 1960.

He met his second wife, veteran radio and TV performer Patricia Lynn, in 1949, while she was touring military bases in Alaska and he was along for the ride as a guest of the Army. She died in 1986.

After Sigmon retired from Golden West Broadcasting in 1970, he dabbled in various business projects and served on Pepperdine University’s board of directors until Parkinson’s disease slowed him down in the late 1990s. In 2002, Pepperdine’s communication program named its radio studio after him, in honor of his contributions to broadcasting.

“He epitomized the Golden Age of radio,” said KNX radio traffic reporter Jim Thornton. “He was so genteel.”

But the SigAlert is his claim to fame. Sigmon’s Lincoln Continental bore personalized license plates that said SIGALRT.

The dreaded “S-word” remains a mystery to many freeway veterans in Southern California. “The most frequently asked question of traffic reporters is, ‘What is a SigAlert?’ ” Thornton said.

Sigmon’s warning system earned him honors from the National Safety Council, the Los Angeles City Council, the Los Angeles County Board of Supervisors and the governor’s office. In late 1998, the longtime Sherman Oaks resident was invited to Caltrans’ L.A. headquarters to dedicate a new control room for monitoring freeways.

“He was a pioneer,” Jarrin said. “The whole point of traffic reporting is to be concise and timely, and he set the table for that.”

Sigmon once told an interviewer, “I’m proud of the fact that the SigAlert system made a contribution. I never tried to make any money off it. In fact, I lost some because I used to bet on a horse named SigAlert that never won.”

Sigmon is survived by two sons, James W. Sigmon of Prescott, Ariz., and David L. Sigmon of Bartlesville, Okla.; five grandchildren; and nine great-grandchildren.

A memorial service is scheduled for 11 a.m. Wednesday at the Little Brown Church in Studio City.