1. The code at this topic was created more than 10 years ago with JDK1.0.2
You might want to check out [url=http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=365.0]Ejs version of traffic control simulation[/url] and working with [url=http://fem.um.es/EjsWiki/index.php]EJS[/url].

2. Please write down what you have done (or what you know about java or programming)?
The timing for red,green,blue light are the same for those three traffic lights (and it can be changed with mouse click--left click to decrease or right click to increase).
You need to define a new GUI to change one of the traffic light, and modify the value for them it the code.
It seems to be an exercise for you. I will try to help but I should not do the job for you.