Can't you just assign the controls to this blank space?
Doesn't work for the car movement for some reason. It just causes it to default back to left and right arrow (making the behavior go back to the whole only turning while moving thing). I forgot to mention that.
I'm not sure if it's a bug or if the blank space is supposed to even do anything. I think it does for other movements, but the car movement just defaults back to left and right arrow if you try to use the blank space.
Edit: I just tried using the blank space to replace the "move left' control on a platform game I was making. And guess what? I tried it in game, and left arrow made my character move left, even though I assigned the key to the blank space.
Well, since this seems like a bug, I'll try to report it using the bug report tool. But that's hardly what I wanted to suggest on this thread. To get back on topic, let me repeat by saying all I'm suggesting is to add a checkbox to make it so that the car can still rotate while stationary. Just a minor little thing, but I still think its a good idea.
Yes, I'm able to achieve the same effect without it, but that's not the point.