When writing the script, Arndt chos

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 [the] 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."[4] Five VW Microbuses were used for the family car as some were modified for different filming techniques.[23] Three of the vans had engines, and the two without were mounted on trailers.[23] 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.[7] 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.[17][24][25]
While filming the scenes where the family pushes the van to get it started, a stunt coordinator was used to ensure the safety of the actors.[6] In an interview, actor Greg Kinnear jokingly described how the scenes were filmed when he was driving: "I was going like 50 miles an hour in this '71 VW van that doesn't have side air bags. Basically you'd wait for this huge camera truck to come whizzing in front of us with the camera. 'Okay, go!' I mean, it was insanity; it's the most dangerous movie I've ever made."[26] While filming the scenes in the van, the actors would at times remain in the vehicle for three or four hours a day.[26] For scenes in which Alan Arkin's character was swearing excessively, Breslin had her headphones on and could not hear the dialogue, just like her character in the film. Only when she saw the film did she know what was being said.[26][27] On July 25, 2006 Fox Searchlight Pictures invited VW bus owners to a screening at Vineland Drive-In theater in Industry, California. Over 60 of the vans were present at the screening.[28]