Car Navigation Map in Canvas

After browsing through the code of Jacob Seidelin's Super Mario Kart demo, I was inspired to take the code and attempt to create a GPS-navigation system experience using publicly available roadmap tiles. The final result is a proof of concept that works pretty damn well in Firefox (and not quite that well in other browsers :).

After passing it around to a few friends, I've already heard some cool suggestions for taking the demo to the next level. So, please, if this inspires you, feel free to experiment further with the code. Enjoy!