I'll spare you the usual novella. I tend to just pound on the keyboard, orangutan style, until my hands get sore, but I'm a bit tired so here's a small one.
I posted up my development list for TurboGarbageTruck. It's not really a design doc. It's really just a list of things that I want to add or test out. I expect that I will grow the list fairly steadily and then drastically hack it down when it grows too unwieldy.
In the latest builds I've been conducting some experiments. I created an infinite terrain setup. Essentially if you drive out the north side of the environment you will come back in the south side. You can drive in one direction forever... or until the physics break and the truck falls through the world. This is just stage one of a larger experiment with continuous environments. So far so good.
The truck flips over way too easily. Working on it.
Also, currently there is no limit to the speed that the truck can reach. You can break the sound barrier in that mofo. Still not sure if that is good or bad.