Well in this picture you can see how close you get to some of the trucks parked on the streets There are white lines that mark the Cable Cars lets say space ,anyone parked over that white line has a good chance to loose a tail light or worse.And of course these backpacks ,be careful and look ahead ,not backwards for long because you might have a problem.
But the bottom line is
RIDING CABLE CARS IS FUN FUN FUN.
What I mean here if you are on the running boards of a Cable Car you better be aware because as you will see in the picture you will get very very close to Cars and trucks .
I nearly got pulled of the Cable Car because my backpack got almost stuck .
Enlarge the picture and you will see that people wear large backpacks on the Cable Car.