There is a one junction simulation: [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=712.0]Time duration for the yellow traffic light[/url].

You can change the delay time, however, the maxmimum speed of each car is chosen  randomly.
Light duration for green and yellow light can be adjusted with slider.
You can download it and modify the code to fit with your need!