I read elsewhere that the plane was only going 24mph when it hit the truck, and I didn't understand how the collision could have been that damaging, but I wasn't taking into account how much momentum a plane would have at that speed. From the video, it seems like a plane moving on the ground acts less like a car or truck and more like a very delicate freight train when it hits something.
I'm not completely sure but it seems like the runway entry lights are red which very clearly indicates the runway is in use. They should have known better.