When a combination vehicle goes around a corner:
The turn should be made as tightly as possible.
The front and rear wheels move in different paths.
The rear wheels should run over the curb.
It is acceptable for street signs to be knocked over if they are too close to the road.
When a vehicle goes around a corner, the rear wheels follow a different path than the front wheels. This is called off-tracking. This effect is especially pronounced on vehicles with trailers.