When writing the script, Arndt chose the Volkswagen T2 Microbus to use for the road trip based on his experience with the vehicle and its practicality for filming: "I remember thinking, it's a road trip, what vehicle are you going to put them in? And VW bus just seems logical, just because you have these high ceilings and these clean sight lines where you can put the camera. In the front windshield looking back and seeing everybody." Five VW Microbuses were used for the family car as some were modified for different filming techniques. Three of the vans had engines, and the two without were mounted on trailers. During pre-production, the cinematographer used a basic video camera and set it up at angles inside the van to determine the best locations to shoot from during filming. Many of the problems associated with the van that were included in the plot (a broken clutch, a stuck horn, and a detached door), were based on similar problems that writer Arndt experienced during a childhood trip that involved the same type of vehicle.