Good Question, I put mine on the passenger side for two reasons, one, If I was to park on a road (at the curb) I could put up the awning and it wouldn't stick out into the street, and the second reason is my Fridge is located at the drivers side passenger door, so if I were to sleep in the back of the rig I would access the sleeping area via the passenger side rear door, which would be shielded by the tarp if it were raining. It would be best to have a tarp on both sides but I cant afford that :sombrero: