Ive just had an idea, and whipped a few sketches. A banked oval with two infield road courses. The short course is simple and rejoins the oval before "pit road". The long course, however, turns right and dips through a tunnel under the banking. There is an outfield section before rejoining the oval on the "back stretch", making it a figure of 8 course.
What do you guys think? Is it worth continuing with?
Also, can anyone help me out with banked turns on sketchup? I cant get my head around it!