lsigmon.jpgDrivers in Southern California owe Loyd C. Sigmon a debt of gratitude. He invented a broadcasting system that allows the police to warn drivers of freeway traffic jams and other emergencies.
While working as an engineer for KMPC-AM radio, Sigmon developed a $600 device that combined a tape recorder with a shortwave radio receiver. When a traffic emergency occurred, a police dispatcher activated the emergency beacon and recorded a message that could be broadcast on the air. Known as the SigAlert, the system was immediately adopted by six local radio stations.
The first SigAlert, which was broadcast on Sept. 5, 1955, requested the assistance of all area doctors and nurses to respond to a train derailment in downtown Los Angeles. The ensuing rush of medical personnel to the accident site actually caused a traffic jam. Future alerts were more successful, featuring reports of rabid dogs, boat collisions and car accidents. One SigAlert announced the news that a pharmacist had made a potentially fatal error while filling a prescription; the customer heard the alert in time and avoided an accidental poisoning.
Local governments and the National Safety Council honored Sigmon for his useful invention. Now computerized, SigAlerts are handled by the California Highway Patrol to report “any unplanned event that causes the closing of one lane of traffic for 30 minutes or more, as opposed to a planned event like road construction, which is planned separately.”
Born in Stigler, Okla., Sigmon was always interested in electronics. He earned his ham radio license at 14, and helped build a radio station in Kansas City, Mo. During World War II, he monitored German radio broadcasts as the head of noncombat radio communications on Gen. Dwight D. Eisenhower’s staff. Sigmon later became a partner in Golden West Broadcasting, but he was best known for his emergency broadcast invention. On his car, personalized license plates read: SIGALRT.
Sigmon died on June 2 of natural causes. He was 95.