ampelmännchen berlin danger directions don't-walk pedestrian pedestrians red sign signs stop street traffic-light Arad blind city lamp light walk window crosswalk hand pictogram urban advice alert announcement appropriate-behavior appropriate-behaviour be-careful beware black care careful caution communicating communication concern crossing dangerous information informing lookout observant risk risks risky road road-sign safety security share sharing speed-reduction street-sign traffic traffic-flow walkers walking warning warning-sign watch watch-out yellow