Expressway's overrun vehicles can't enjoy the free policy, but in order to avoid the error of the weighbridge, the error range of 5% is given.

It is the error range of 5% of the load limit of the vehicle itself.

For example, the load limit of a six-axle truck is 49 tons, 49 tons x5%=2.45 tons, 49 tons +2.45 tons =5 1.45 tons, which means that a six-axle green car can be free if it does not exceed 5 1.45 tons.