It means that if the car exceeds a certain distance, it will run empty when it comes back. If this fee is not added, the driver of this order will lose (or earn less) and the driver will not accept this order.
If this fee is not added, some drivers will be unwilling to go out of the city with their tickets, and as passengers, they will not be able to reach their destinations. Especially drip cars, which are generally private cars, have high fuel consumption (taxis will take a breath), so you have to pay for an empty trip.
Extended data
Empty driving fee is the freight charged by the carrier to the shipper according to the regulations when the operating car is idling at the request of the shipper.
There are generally three kinds of idle driving fees: loading and unloading mileage fee, adjustment fee and loading failure loss fee.
(1) Loading and unloading mileage fee: 50% of the actual mileage of the vehicle from the station (garage) to the loading place plus the unloading place to the nearby station (garage). All provinces, municipalities and autonomous regions may, according to the specific circumstances, stipulate that no loading and unloading mileage fees are charged.
(2) Fare adjustment: At the request of the shipper, if the operating vehicle is temporarily transferred from the station to participate in the operation and is driven empty, the empty driving fee shall be charged at 50% of the calibrated tonnage of the vehicle and the basic freight rate at the transfer place according to the full round-trip empty driving distance.
(3) Loss fee for loading failure: If the vehicle is not loaded at the agreed place, resulting in idling mileage, the idling fee will be charged at 50% of the basic freight rate.
Idle driving fee refers to the cost of transferring the vehicle from the outside station to the bus station when there is no required vehicle at the bus station designated by the contractor, and returning the vehicle to the station where the original vehicle is located after use or returning the vehicle to the station where the vehicle is located after one-way use. Idle driving fee is calculated according to the shortest path.
References:
Air ticket-Baidu encyclopedia