If the dinosaurs had developed automobiles, then aside from increased levels of carbon dioxide before humanity ever appeared perhaps we would be inheriting disused parking structures along with oil? Though considering oil is in fact mostly old dinosaurs that have liquefied and become explosive then maybe dinosaurs would have had solar powered cars, as the sun has been around for quite a while.
I reckon a Stegosaurus would drive a family station wagon. I imagine they care about getting the troop to the theme parks in a safe and productive manner.
The T-Rex might seem like a sports car kind of dinosaur, but this is a ruse. The arms, you see. Tricky to operate any car, plus the height. I think they would be enjoying a camper van.
The Diplodocus (my favourite of the dinos) would probably have a bus, in order to keep their tail safe from the trials of the roads, though they were probably not tarmac, maybe some kind of foliage type thingy, via compressed tree leaves?
More likely, though the dinosaurs would not even care about driving and vehicles, considering they have the beef trunk legs to cross the large distances, and they did not have shopping centres or capitalism.