Brian Beckman, author of the Physics of Racing series (for which I am mighty grateful), has a video up on Channel 9 talking about the complexity of modeling vehicle dynamics, tires in particular. I had no idea he was working at Microsoft, on programming tools of all things, but apparently he's been there quite some time. If you've ever attempted to implement tire slip ratios (hasn't everyone?) this will all sound very familiar; it is reassuring to know that even a Very Smart Person like Dr. Beckman has the same troubles.