Interestingly, the self-driving Uber vehicles will mandate human intervention when going over bridges. When approaching a bridge, the car will chime--indicating that a human driver will need to take over. "Bridges are hard," Krikorian told Bloomberg, saying this was due to bridges offering fewer landmarks the computer can use to figure out where to go. The computer uses buildings, street signs, trees as indicators of how to proceed. With a bridge providing simply one giant body of water as your surroundings, it's best at the moment that a person handle that part of the trip. At the end of the bridge, the computer is once again able to take control.