It takes a lot of courage (or health tests beforehand) to play a prank like the one Ford played on 30 strangers who were on their way to a filmed test drive.
Ford instructed them to stop for a car wash before they reached their destination, which obviously they did. What they didn’t know was the car wash was a trap, with employees wearing Halloween monster costumes and trying to scare the heck out the people inside the cars.
Judging from the passengers’ reactions, it seems they did a pretty good job. And while it’s the sort of prank you recognize as such right from the beginning, somehow the screams didn’t stop inside the car until the prank was over. Either they were really scared, or they’re good actors. I’m inclined to go with the latter, but you can judge for yourself by watching the video.