At the end of the talk, and article, there is a short video demostration of the current state of the game engine, and it has hills and banked curves and whatnot. For the talk I opted for a flat grid.

Suspension is implemented as well but it didn't feel to me like a unique problem to implement for cars, at least not a simple suspension that can carry a car, and it didn't fit too well with the flow and limited time I planned for this.