  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.
