Within a couple of miles of here, there are two Victorian railway bridges.
One is only wide enough for one car to pass under at any time, the other is passable by two vehicles travelling in opposite directions, though perhaps not if one is a van or lorry, but is askew by about 30° giving a small kink to the road.
The first is always negotiated very comfortably with drivers exercising common sense and courtesy. I have been under this bridge thousands of times in my 40+ years and have never witnessed any misunderstanding, angry gestures, road rage. Nothing. Ever.
Same with the second bridge ... until, about a year ago, the council decided to install one of these signs for those approaching from just one direction.
Since then, the incidences of angry exchanges, flashing lights, horns and even near (deliberate) collisions have been regular. And that's just from my personal experience.
It's the same bridge, the same width of road, nothing has changed. Except that the placement of that sign has given a feeling of superiority to those approaching from the south, whilst also at times intimidating those coming from the north into stopping where there is no rational need.
As Raedwald has mentioned before, and I have also commented on previously, authoritative road directions always lead to the same outcomes - they remove the requirement of thought to some drivers and hinder progress whilst arguably increasing risk.
There are other 'chicanes' in our area (not involving bridges) where these signs are not erected, and again traffic passes smoothly and malice free compared with others where the prescribed priority encourages bossy, and sometimes dangerous, behaviour.
I believe there's a metaphor here for the reduction of authoritarian local, and national, government.
People, left to their own cognisance, weigh up choices better, think more, and are less confrontational to others in their community than if given ever more petty, and largely unnecessary, rules.
Sometimes, it would be better that public sector rubber band flickers carry on doing just that, rather than feeling that they should 'do something'.