People new to Southern California are always asking me what a SigAlert is. According to the Highway Patrol, a SigAlert is “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”. You can read more about the history of SigAlerts on “This is a SigAlert Message“, a wonderful site by Harry Marnell. Of course if you really want to be in the know, check out the CHP Traffic Incident Information Page.
The other thing people ask me is what those crazy fan things on the top of billboards are. Some have suggested that it is to generate power for the sign, but in reality, it is just to keep the birds off the sign.