More on the Simulator
If you focus on the pillars holding up the garage you can see the shadows being cast and how the interior supports are completely shadowed while the outermost pillars are not. The way this usually works is by choosing a time of day and just painting the shadows on the parking stucture which is much easier for the computer. The problem with that technique is that when the sun sets you have the same shadows on the buildings as you did at 2PM.
The benefit of not taking shortcuts is that a) we don't have to hand paint shadows onto everything and b) we can move the sun across the sky easily to simulate atmospheric effects and even create a race that transitions from day to night. The first real release of the simulator is probably less than a month away, I'm going to document the progress here as a sort of time capsule for future reference.