Hello 127logs, just a curios.
I see, if we want to prohibit no_u_turn for truck.
In the official OSM wiki: https://wiki.openstreetmap.org/wiki/Relation:restriction

There is restriction:hgv but in most routing engine like OSRM, Valhalla they don't understand the restriction:hgv 
https://github.com/search?q=repo%3Avalhalla%2Fvalhalla%20restriction&type=code

Therefore i suggest a new kind of tagging. We should mark like:
restriction=no_u_turn
except=bicycle;motorcycle;motorcar;bus
Then only when user choose their prefered vehicle=truck, they will being directed to another link.
