IOW, my truck is bigger than your truck. Or equivalently My penis is smaller than your penis.
That seemed to literally be the de facto rules in Vietnam when I visited in 2019. The bigger your vehicle was, the more directly you’re allowed to move from Point A to Point B. The key was, you had to do it slowly enough that everyone around you could figure out how to go around you to get to Point C.
We were on a large tour bus, and on the main highway, he plopped himself right in the middle, straddling the center line, and only deviated when a vehicle of comparable size was coming the other way. How much he deviated depended on the relative size differential.
Everyone else on motorcycles and the like just passed the bus any way they wanted, left and right sides, like water passing a rock in a stream.
That is pretty much 3rd world standard driving. I saw the same in Panamá too.
The busses & trucks acted like they were the only things on the road. The cars acted like they were the only things on the road except for the “fixed” obstacles of the busses and trucks. The motorcycles & motorscooters likewise vs the busses, trucks, & cars, with the pedestrians taking up Tail-end Charlie position in the hierarchy.
Such fun.