One thing I find somewhat arcane and that is, with Michigan's extremely high GVW weight restrictions (165 thousand on 11 axles) and no Federal Bridge Formula applied (and yes, for years I piloted an 11 axle Michigan 'sled', delivering steel), road building and rebuilding here follows the other states in how they are built and rebuilt and that is way sub standard for the GVW allowed here.
Working on 23 North, north of Milan to Ann Arbor and resurfacing with hot top (asphalt) instead of totally removing the road, excavating the underlayment and topping with concrete and rebar. Total waste of tax dollars and the road will be pothole city in less than 2 winters.
Only reinforced concrete can carry the weight here in Michigan and the overpasses are in the same deteriorating boat as well. That 165 kicker tag on the plate ain't cheap either.
The way it plays is:
13K on each trailer axle ( times 8, plus 34K on the drives and the balance on the steer, predicated by tire width and front axle capacity). It is possible and done often by spacing the lead axle on the trailer over 8' from the second axle (has to be on air) and that allows you 20K instead of 13 but the gross weight don't change. Sled drivers do that to increase the margin before overloading an axle and the over weight fines are steep here as well. Interestingly, all overweight fines as well as equipment fines go to the local library system under state statute, something most Michigander don't realize.