If you are talking about the 1200 in the video, it is in Southern California. Contractors name at the end of the video, WA Rasic
The truck is in a closed lane, and there is about a lane between it and traffic, and there is a K rail barrier. It is a major thouroughfare, and no viable detour was available. There was lots of safety involved, and no accideents I was aware of. Very hard digging, and no blasting allowed due to high pressure gas main parallel to the trench. It had been blasted in years ago, before the area was built up.
I really don't see the problem you are seeing, as it is common practice here to work close to traffic, and very few problems come of it on a properly managed site.
By the way, the agency the work is being done for is known to be one of the toughest around on following safety orders, as well as general work details. They go overboard enough many contractors refuse to bid their work.