Self-driving Car: The self-driving car has no certain route. It just run on the roads and randomly decide which way to go. The car has ability to observe the speed and distance of the object ahead. Then, it will decide to speed up or down to avoid accident. The car follows regular traffic rules, stop at red and go at green.
Pedestrian: 10 pedestrians will be released to random positions around the whole map. Each one of them will observe the car distance and traffic light. After calculating his own speed and car speed, the certain pedestrian will make its own decision to decide if he would cross the street. Some time the calculation might be wrong and the walker will still cross the road.
NPC Vehicle: Moves as a fixed route and speed. Stop when the closest traffic light is red. If there is a car or walker in front of the NPC vehicle, it stops too.
Traffic Light: The lights will just simply follow the cycle: "Red→Yellow→Green→Yellow→Red". Each crossroads has two traffic lights and the colors of the two traffic lights will be counter. For example, when one of them is red, the other one should be green.
Map: The map is a 3*3 grid, mashed by 4 streets. Every crossover point will be set 2 traffic lights.