Then a directed network graph is constructed from road data using JGraphT library. Cars are initialized, and a list of routes is generated with a Dijkstra shortest path algorithm. Then cars are assigned a random route and set on their way. When a car reaches destination, it’s removed from the list, and a new car is spawned.
Whole sketch with data is here for download. I used Eclipse and then transferred it to Processing, so there are pure Java classes in it.
You will probably have to run it in 32-bit Processing 1.5.1. It won’t work on Processing 2.0, because there have been significant changes with OpenGL. There’s also a possibility it won’t run on 64-bit Processing because of JGraphT library. I had one such report.
My other project with GlGraphics here.