Using the arduino you can make two pedestrain crossing traffic lights that will change when a button is pressed, pause for 15 seconds then revert back to the original state.

This project will make a working traffic light system. One traffic light will be for cars and the other for pedestrains. If the pedestrain want to cross the road they will press the button. The traffic light wil wait before turning orange then green for the pedstrian and orange then red for the cars. 15 seconds later they will switch back letting the cars carry on.

All you need to do is put everything in the correct place as shown on the diagram, run the script and it should work. I created this myself and so far there has been no failures.