Many e-commerce marketplaces offer their users fast delivery options for free to meet the increasing needs of users, imposing an excessive burden on city logistics. Therefore, understanding e-commerce users' preference for delivery options is a key to designing logistics policies. To this end, this study designs a stated choice survey in which respondents are faced with choice tasks among different delivery options and time slots, which was completed by 4,062 users from the three major metropolitan areas in Japan. To analyze the data, mixed logit models capturing taste heterogeneity as well as flexible substitution patterns have been estimated. The model estimation results indicate that delivery attributes including fee, time, and time slot size are significant determinants of the delivery option choices. Associations between users' preferences and socio-demographic characteristics, such as age, gender, teleworking frequency and the presence of a delivery box, were also suggested. Moreover, we analyzed two willingness-to-pay measures for delivery, namely, the value of delivery time savings (VODT) and the value of time slot shortening (VOTS), and applied a non-semiparametric approach to estimate their distributions in a data-oriented manner. Although VODT has a large heterogeneity among respondents, the estimated median VODT is 25.6 JPY/day, implying that more than half of the respondents would wait an additional day if the delivery fee were increased by only 26 JPY, that is, they do not necessarily need a fast delivery option but often request it when cheap or almost free. Moreover, VOTS was found to be low, distributed with the median of 5.0 JPY/hour; that is, users do not highly value the reduction in time slot size in monetary terms. These findings on e-commerce users' preferences can help in designing levels of service for last-mile delivery to significantly improve its efficiency.

翻译：许多电子商务平台为了满足用户日益增长的需求，向其提供免费快速配送选项，这给城市物流带来了过重负担。因此，理解电子商务用户对配送选项的偏好是设计物流政策的关键。为此，本研究设计了一项陈述偏好调查，让受访者面对不同配送选项和时间段的择项任务，该调查由来自日本三大都市圈的4,062名用户完成。为分析数据，我们估计了能够捕捉口味异质性及灵活替代模式的混合logit模型。模型估计结果表明，配送属性（包括费用、时间及时间段长度）是配送选项选择的重要决定因素。同时，用户的偏好与社会人口学特征（如年龄、性别、远程办公频率及是否有快递柜）之间存在关联。此外，我们分析了两种配送支付意愿指标，即配送时间节约价值（VODT）和时段缩短价值（VOTS），并采用非参数方法以数据驱动方式估计其分布。尽管VODT在受访者间存在较大异质性，其中位估计值为25.6日元/天，这意味着若配送费仅提高26日元，超过半数受访者宁愿多等一天——即用户未必需要快速配送，而是在费用低廉或近乎免费时才倾向于选择。此外，VOTS的中位值为5.0日元/小时，表明用户对缩短时间段的货币价值评价不高。这些关于电子商务用户偏好的发现有助于设计最后一公里配送的服务水平，从而显著提升其效率。