The ubiquitous sigalert. SigAlert, actually. Doesn't mean "signal alert," or anything else you might think. It's named after the guy who made it up to boost ratings, Lloyd Sigmon.
SigAlerts are now officially issued when one or more lanes of traffic will be blocked for at leat 30 minutes.
Sigmon has died in Oklahoma at age 95. A memorial service will be held Wednesday in Studio City and I'll let you write your own jokes on the traffic implications of his funeral procession.