Countdown Crossing In London
Digital timers now count down the number of seconds you have left to cross the road, at 8 major junctions in London.
The trial's costing £750,000, the Mayor says a fifth of pedestrian deaths and serious injuries happen at these types of crossings.
The city is following in the footsteps of places like New York, Toronto and Auckland, where they've already been successful.
The trial sites include Oxford Circus, outside Southwark tube and outside Balham station.