Conclusion and future research

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This research aimed to identify, through a systematic literature review, new ways of operating the last mile distribution in urban areas and the technologies related to it. Specifically, the main features of the vehicles, the barriers, opportunities and benefits (economic, environmental and social) of their use, as well as the delivery extensions of each case, were identified.
It has been observed a trend towards a size reduction of the vehicles (likewise capacity) used for last mile deliveries in urban areas. It is noteworthy that pressures imposed on traffic, due to aspects related to land use, like restrictions on the trucks movement and geographic/historical aspects have made the operation of last mile deliveries, traditionally done by trucks, a challenge for all actors involved. For this reason, the observed frequency of references suggests that deliveries should be done by bicycles/tricycles/motorcycles (42%) and light commercial vehicles, identified in 58% of the occurrences. However, there are still cultural barriers related to the acceptability of customers in signing contracts with companies that operate with alternative vehicles, especially bicycles.
In addition, it was observed the migration of the source of vehicles propulsion to electric energy, indicated in 69% of the studies, in detriment to the fossil fuels. These data show a concern, not just to avoid the adverse effects of a congested road network, but also to take measures based on the social and environmental sustainability of urban freight transportation. Therefore, it is fundamental to develop new studies that analyze how the growth of electric vehicles can be integrated into the supply chain and how it can be an opportunity for cooperation between all the stakeholders.
These trends imply further issues that require more studies, such as the consequences for the operational level of service by increasing the number of trips made by even smaller vehicles and how to adapt the road network to integrate these types of vehicles, notably bicycles and tricycles.