An enclosed array of lights mounted on top of
emergency vehicles for the purpose of either moving traffic out of the way or alerting the public to the presence of an
emergency.
Lightbars can come in different types. The most common consists of rotating spherical mirrors around a light to cause quite a light display. Sometimes these rotators are spread out such as in a V-shape, a vector lightbar, most notably used by the NYPD. Recently LED lightbars emerged into emergency lighting due to their more
efficient energy usage.