[quote]Why not a car or bus?[/quote] Because when Scooby Doo was introduced, highly stylized vans were the big custom car thing at that time. So it just made sense. Plus it would a car would have been too small. A bus was already being used for a tv show of that era called The Partridge Family. Would have been too similar. [quote]Also why is it named the mystery machine?[/quote] Because it was again, what was going on in that era with the stylized vans. The only thing that was missing was a custom interior with shag carpeting all over the floor, walls, and ceiling, and a bed. [url=https://www.google.com/search?q=70%27s+custom+vans&rlz=1C1CHBF_enUS724US724&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjrqNy-v4PdAhWBiYMKHUauAIEQ_AUICygC&biw=1536&bih=738]Check these out[/url] You'll notice a lot of them are named.