# The Electric Vehicle Routing Problem with Time Windows, Partial Readers, and Parcel Lockers
## 2 Related Work
### Delivery Options in Last-Mile Delivery  
Logistic companies face challenges in the sustainability and efficiency of their delivery networks due to factors such as traditional vehicles, traffic congestion, and urbanization [31]. A comprehensive review of recent and future last-mile delivery concepts is presented by ref. [9], who emphasize the significant benefits of alternative delivery options and address key decision problems using established operations research methods.  
Regarding alternative delivery options, the concept of considering multiple time windows for each customer was first introduced by ref. [32], called VRP with multiple time windows (VRPMTW). Later, several variants of VRPMTW are studied, such as VRP with multiple interdependent time windows [33] and VRP with multiple prioritized time windows [34]. In addition, [PERSON] et al. [35] develop a hybrid variable neighborhood tabu search heuristic to effectively solve VRPMTW. [PERSON] et al. [36] further extend VRPMTW to VRP with roaming delivery locations (VRPRDL), where multiple delivery locations are provided with different non-overlapping time slots for customers. [PERSON] et al. [37] offer an exact algorithm to solve both VRPRDL and the dynamic version of VRPRDL proposed by ref. [38]. In the dynamic version, routing plans are rescheduled in response to changes during the transportation execution. Another extension of VRPRDL is proposed by ref. [39], where parcel lockers are used as shared delivery locations with limited service capacities, replacing the trunks of cars. In addition, [PERSON] et al. [40] extend VRP with delivery options (VRPDO), where customers' parcels can be delivered to various locations such as their private addresses, lockers, or car trunks.  
Parcel lockers are especially used for proposing a delivery method (i.e., the self-pickup method where customers pick up the packages by themselves), which provides more flexibility and efficiency in serving customers. The use of parcel lockers in last-mile delivery can reduce up to 66% of total delivery costs compared with traditional methods [8]. Applications for parcel lockers for current and future logistics networks have been presented in a survey conducted by ref. [9]. [PERSON] et al. [41] investigate parcel lockers into a two-echelon VRP, where each customer can be served at either their home or a designated shared location (i.e., parcel locker), but time windows are not considered. [PERSON] and [PERSON] [42] address alternative delivery methods to accommodate customer preferences where the capacity of shared locations (i.e., parcel lockers and post offices) is limited. [PERSON] et al. [43] use parcel lockers as covering locations where nearby customers can pick up their parcels. This problem provides two delivery options: self-pickup and home delivery. [PERSON] et al. [44] compare the advantages of parcel lockers in reducing pollution by evaluating the results obtained from home delivery systems and parcel locker systems. Their findings contribute to understanding the positive environmental impact of parcel lockers as an alternative delivery method. [PERSON] et al. [45] address the use of parcel lockers in VRPTW, which provides three delivery methods for serving customers. The concept of delivery methods in this paper is investigated in our problem. Other studies also investigate the applications of parcel lockers in last-mile delivery, such as automated parcel locker systems [46] and heterogeneous locker boxes [47].