Sentence:  Rogan hit the <WSD>wigwag</WSD> flashers on the headlights of the Crown Vic and made it to the circular driveway at the Sixth Avenue entrance of the Hilton in four minutes flat. 
Meaning of the word marked with <WSD> tags:  A device used to cause lamps installed on a motor vehicle, especially an emergency vehicle such as an ambulance or police car, to flash as a warning.