In the end it's up to our interpretation, though they do have wheels so that seems unlikely.

Those fin=like parts made think that, I'm making a Hell's Gate replica in Minecraft, thought I throw them in. I don't even know which end is the front and which is the back, though I asked this question my mom and a few friends, and said that the left side is the front, these things that I thought were engiones could be the front lights, and on the two other cars, the ones with the fins, they have a red piece on the right side of the picture, which could be the back lights given that the back lights on cars ar made out of red glass. the triangular part seen on the car below I believe to be the window and/or door, I'm not sure about that though, it had lines on it, which could be how the car opens.
http://i.imgur.com/azayZXQ.jpg