Look at these website for traffic modelling on computer:

http://www.traffic-simulation.de/

Also these short movies for visualising traffic

http://www.vwi.tu-dresden.de/~treiber/movie3d/index.html

Here is a list of computer simulations from wikipedia

http://en.wikipedia.org/wiki/Computer_simulation#Examples

Homework – Find one of the simulations which interests you and play around with the different variables