He didn't strap the dog to the roof of the car. The dog was in dog crate that he strapped on the roof of the car.
wind going through the holes in a crate has got to hurt. Was there any type of windshield in front of that crate?
In a pick up truck, there is a windshield. There isn’t one on a roof.
There should be an experiment conducted. Place a person in a crate on a car roof and drive 70 mph. Then place same person on the back of a PU and drive at 70mph. Then ask the person which ride they enjoyed most. Better yet, have the person blindfolded so they don’t know where on a vehicle they are.