It is a home-made semaphore controlled by EasyAVR6 board. Semaphore control can become a whole science, and you can have a whole city controlled by a central computer, and if you hack into the system you can make your passage through the crowded streets, like in the movie Hackers :)
Anyway, this is not such a project, but a bit less complex one. Although it seems simple, having a precise timing for semaphores and synchronization between crosswalk signalization for pedestrians and cars is crucial for public safety.
Throw an eye on how the project was done using Relay4 boards, so you might consider making your own semaphore and a crosswalk :)
[click on the image to enlarge]