States do have weight laws that apply to all vehicles. Not just commercial trucks.
The lawyer thing posted is correct. Having towed commercially I would add not only can we face a civil lawsuit but dot will impound our vehicles.....issues fines....pull CDLs/etc. However for being over the trucks legal load limit which the truck makers GVWR has no legal implications period. We don't see civil lawsuits/dot tickets in the commercial side of trucking for exceeding a truck makers GVWR....but we sure do if were over the vehicle legal load limit.
All vehicles on the road come under axle/tire load limits (non commercial or commercial).