As he pushed the individual cars around he said things like "Here comes the music car" and "Hey, what about me? I'm being polite."
I would say that is proof that he has never seen or been to a real car race!
His play has advanced recently into some magnificent story telling. I have to keep from laughing with all of his "play" dialogues. The other day he was playing with a robot toy and the toy said "I am very hungry" so Luke replied "We need to go find your mom so you can get some food!" That particular dialogue went on and on. Okay sometimes I do burst forth with a laugh and then he thinks he is the cleverest! His imagination inspires me.