"Don't look down" - sensible advice if you're a) on top of something tall, b) standing in a pit of something utterly horrible or c) approaching a road whilst glued to your smartphone.
It's advice that failed to have any impact in the German city of Augsburg, where several mobile users were injured by walking into the path of oncoming trams. As conventional pedestrian lights, tram horns and warning signs failed to have any impact, the local authorities have taken the additional step of installing ground-level traffic lights to a tram stop.
Two rows of LEDs are built into the pavement to act as one final chance for a phone-gazer to realise their impending doom. Earlier this year, a girl was killed stepping in front of a tram in Munich after she failed to notice it, engrossed in her smartphone while wearing headphones.
Here's hoping the new lights are more effective.