The underlying concept is straightforward: in order for supermarkets to optimise their delivery schedules, they typically need larger delivery time slots. More efficient delivery routes result in reduced logistics costs as well as a significant decrease in CO₂ emissions.

But how can customers be persuaded to opt for more flexible delivery time slots? In a study recently published, Eleonora Rizzitello, Giovanna Lo Nigro, Simona Mancini (Department of Engineering, University of Palermo) together with Margaretha Gansterer (Production Management and Logistics Unit, University of Klagenfurt) show how nudging can influence the behaviour of online grocery shoppers in ways that significantly reduce logistics costs and emissions. To this end, they first conducted an empirical study, testing various approaches on a sample of 700 customers of an Italian supermarket chain. Margaretha Gansterer explains: “The aim of the study was to determine whether participants were willing to deviate from their preferred delivery time slots to allow for greater flexibility in distribution.”

She summarises the results as follows: “When test subjects are told how much CO₂ can be saved by being flexible about delivery time slots, they are quite willing to give up a short time slot. This green nudge was even more effective than financial incentives such as discounts, which we also tested in the study.”
In addition, peer pressure was found to exert a strong influence. “People who did not initially respond to the nudges agreed to the flexible supply chain once they realised that several others had already given up their preferred delivery slots.”

The research team then applied these empirical findings to the optimisation model for route planning. They were able to demonstrate that consolidation effects can reduce transport costs and, consequently, emissions by more than 70%.

The solution proposed by the researchers is the introduction of a shared shopping cart, which bundles orders from neighbours and thus significantly reduces delivery costs. “When consumers see that others share their commitment to sustainable behaviour, it reinforces their own environmentally friendly decisions. The shared shopping trolley provides an opportunity to promote collective environmental action while also cutting last-mile delivery costs in the food sector,” Margaretha Gansterer concludes.