Gas, brake, gas, brake... guess what is next? Oh, well, it is gas again... But watching out for speed is simply a necessity in a busy city, otherwise there would be cars crashing every single minute or maybe even more often. Control traffic during the busiest period of the day and make sure that all cars run through the intersection without any problems. That means: no crash, no scrapped metal, no argues between drivers about who is going first. This sounds pretty easy on paper, but reality can often be very cruel. Have fun.