The project is working that when the ambulance comes the traffic light is green. After the ambulance passes, it returns to normal operation. We used a button as a sensor because there is no sensor and we cannot model it in Proteus ISIS. The logic of the sensor and the button is the same as the logic of binary code. When you see the ambulance, the button will be pressed, so the green light will be on. After the 5 seconds (we can change this time from the source codes of the programme) i said 5 seconds and i set it to 5 seconds. Also, the ambulance will not stay for 10 hours because the middle of the road. After the 5 seconds of stay and ambulance passed, the traffic light will return to normal working flow again.