Working with the Lead Designer on Asphalt 6, I was primarily responsible for technical implementation of the tracks, as well as their designs. I would create a basic block mesh in 3DSMax so that we could test the layouts in-game, and iterate on that until it was ready to pass to the artists. I was responsible for virtually all of the technical aspects of the tracks; collisions, AI splines, traffic cars, skyboxes, etc.
I managed a team of technical game designers, where we did pickup placement, created track camera previews, and so on. I also provided basic debugging support for the team :)