A pelican crossing is a type of pedestrian crossing with traffic signals for both pedestrians and vehicular traffic, activated by call buttons for pedestrians, with the walk signal being directly across the road. The name "pelican" is derived from "PEdestrian LIght CONtrolled," which is a portmanteau of pedestrian light controlled. Pedestrians must press a button on the black and yellow box to illuminate the "WAIT" sign, and when the traffic lights turn red, the green man will appear on the opposite side of the road, indicating that it is safe to cross. Once the pedestrian signal has been green for a certain amount of time, it will then start to flash. If pedestrians are still in the road when this happens, they are safe to proceed, but they must not begin to cross on a flashing green or solid red man. Pelican crossings differ from zebra crossings in that the flow of traffic is controlled by traffic lights, and pedestrians waiting at a pelican crossing are able to press a button that changes the traffic lights to red. Pelican crossings are the only crossings that have a different sequence, which goes red, flashing amber, green, amber, red, and flashing amber means that if pedestrians are on the crossing, they can continue to cross but should not start to cross.