Yikes!! So it looks to me like they run the car up to top gear, then apply the air brakes on the truck rear-end and measure the force on the load cell... Does not seem like a good idea to me. Things are going to happen really fast at that point - BAD things! (Insert gratuitous Chevy remarks here)
The one thing I see missing is the empty beer cans laying around everywhere.
I sure hope no one gets hurt. But I have to say it's hilarious.