Hello everybody ,
the question might be strange but here it is .
as an overall if you were going to implement a traffic game, what is the best way to implement the behavior of cars with different speeds? how to avoid collisions between cars from different roads ? , how to make the cars choose from different paths ?
and so on… how to make the game 
.
i know the question is a bit stupid but i really wanna someone to answer it , really thanks in advance
Break up the problem into smaller problems, think about it and if you have trouble, ask a constructive, clear question here. We are not here to tell you how to make a specific game, we are here to help you with small pieces you have trouble with.