Understanding off-hour deliveries in cities: a critical review of determinants and impacts

Freight delivery vehicles in urban areas have both advantages and disadvantages: they serve the urban economy but also contribute to significant negative externalities, including but not limited to environmental pollution and traffic congestion. To mitigate their negative impacts, the concept of off-hour delivery (OHD), which shifts delivery vehicles from daytime to nighttime, is gaining popularity worldwide. For successful implementation of the strategy and more informed decision-making by public sectors, this paper reviews academic studies on (a) determinants of OHD including business attributes, logistical factors, policy instruments, and stakeholder perspectives and (b) its impacts on traffic, energy and emissions, and operations. As a result, the review highlights the need for carefully designed OHD programmes that account for key determinants such as receiver participation and the role of incentives. The evidence confirms that OHD can substantially improve traffic conditions (e.g. increases in truck speeds of up to 200% and reductions in travel times of up to 52%) and reduce energy use and emissions (fuel savings of up to 17% and emission reductions of up to 70%), while noting the importance of mitigating potential nighttime noise. The review also identifies critical knowledge gaps, including limited empirical evidence beyond simulation studies and the need to assess OHD within the context of emerging trends such as electrification and home deliveries.