Table 3 Notation for key parameters used in the evaluation indicators.
From: New approaches and performance analysis of on-demand delivery systems using buses
Notations | Definition | Unit |
|---|---|---|
\(A\) | Set of delivery demands in one day, \(A = \{ 1,2,3...a\}\): Calculated based on actual data | – |
\(l\) | The delivery distance of the delivery demand.: The distance of the shortest path from the origin to the destination based on the road network | km |
\(l_{c}\) | The delivery distance of professional crowd shipper: Calculated based on the shortest path algorithm | km |
\(l_{b}\) | The delivery distance of buses | km |
\(l_{r}\) | The distance between the bus stop and the delivery destination | km |
\(n\) | The number of bus transfers when delivery parcels | – |
\(C_{{\text{B}}}\) | The cost of installing all lockers inside the buses: The cost to install a locker is 500 CNY | CNY |
\(C_{S}\) | The cost of all temporary storage facilities: The cost to install an intelligent courier locker is 10,000 CNY, and the rental cost of a retail store is 20 CNY/day | CNY |
\(C_{{\text{c}}}\) | The delivery cost by professional crowd shippers. The initial transportation fee is set at 6.4 CNY for distances up to 3 km. An additional charge of 1.8 CNY/kilometer applies for distances exceeding the initial range26 | CNY/km |
\(C_{b}\) | The cost of transporting parcels by bus for one trip: Assuming the space occupied by a parcel on a bus is 1/4 of the space occupied by a passenger and the bus fare for each passenger is 2 CNY27, the cost of bus transport for a parcel is calculated to be 0.5 CNY per parcel. An additional 0.5 CNY is added for each transfer | CNY/trip |
\(C_{a}\) | The labor cost paid to bus terminal sorting staff: 150 CNY/day per staff member with one staff member assigned to each station | CNY/day |
\(C_{p}\) | The cost of transporting one item of parcel for passengers: 1.5 CNY /kilometer | CNY/km |
\(C_{r}\) | The delivery cost for residents acting as crowd-sourced delivery: Delivery within 500 m is 0.5 CNY, with an increase of 0.5 CNY for each additional 500 meters11 | CNY/km |
\(t_{b}\) | The bus travel time: calculated from the speed of bus, bus: 25 km/h | min |
\(t_{w}\) | Bus travel and waiting time: Calculated based on bus departure time | min |
\(t_{c}\) | The professional crowd shipper’s delivery time: Calculated from the speed of transport, electric bicycles: 20 km/h | min |
\(t_{e}\) | The sorting time at the bus terminals: Sorting a parcel takes 3 min | min |
\(t_{p}\) | min | |
\(t_{r}\) | The walking time from the origin/destination to the parcel temporary storage station: Calculated from the speed of transport, walk: 7 km/h | min |
\(E_{b}\) | The electrical energy consumed by buses: A bus can transport multiple parcels, and the average single parcel consumption of electrical energy is calculated when the bus is fully loaded .A single piece of parcel consumes 4 w/km28 | w/km |
\(E_{c}\) | The electrical energy consumed by e-bikes: In the scenario where professional crowd shippers can consolidate deliveries, each electric bicycle transports four parcels. A single parcel consumes 50 w/km29 | w/km |
\(E_{s}\) | The electrical energy consumed by the intelligent courier locker: A single piece of parcel consumes 25 w/day30 | w/km |
\(O_{b}\) | A single parcel that takes up road width by bus: Occupation of road area of a bus is 30m2, (according to the Urban Road Engineering Design Code, in China) and a single parcel takes up road space is 0.43 m | m |
\(O_{c}\) | A single parcel that takes up road width by e-bikes: Occupation of road area of an electric bicycle is 1.158 m2(according to the Urban Road Engineering Design Code, in China), and a single parcel takes up road space is 0.54 m | m |
