Probably not sped up. What you're seeing is a sudden acceleration of the camera's viewpoint when panning to the left in order to keep up with the 1.9s to get to 60mph.
Looks more like they jumped out of surprise rather than the movements being artificially sped up.
I didn't speed up the video. That is the original.
What can you see?
Would be good to get an answer on this from the author since he was so kind to show up.