Sig-Alert - Overturned Vehicle - Peppertree Canyon.
What are Sig-Alerts? "Sig-Alerts" are unique to Southern California. They came about in the 1940s when the L.A.P.D. got in the habit of alerting a local radio reporter, Loyd Sigmon, of bad car wrecks on city streets. These notifications became known as "Sig-Alerts." Later Mr. Sigmon developed an electronic device that authorities could use to alert the media of disasters. Caltrans latched on to the term "Sig-Alert" and it has come to be known as any traffic incident that will tie up two or more lanes of a freeway for two or more hours.
Source: http://www.dot.ca.gov/hq/paffairs/faq/faq18.htm #sigalert #peppertreecanyon #santaclarita