Grocery delivery services have seen rapid growth in recent years. Is this a sustainable practice or a congestion generator and an environmental burden?
Researchers from Carnegie Mellon University (USA) developed a method to estimate changes in travel patterns caused by grocery delivery adoption (a method to modify travel demand data to reflect changes in travel patterns caused by people switching from in-person to online grocery delivery) and apply it to a case study in car-dominated Seattle, WA (USA). The goal of this research was to develop a transferable and flexible framework that could be quickly adopted by practitioners to assess the congestion, emissions, and energy impacts of online grocery delivery and to understand the magnitude of the effects of important variables such as complementary vs. substitution shopping behaviors and delivery routing operational decisions.
Results suggest that delivery can increase or decrease peak hour emissions (−0.9% to + 4.9%) and vehicle hours traveled (−4.2% to + 6.3%), depending most critically on (1) delivery center location, (2) whether deliveries displace dedicated or non-dedicated shopping trips, (3) the degree to which delivery replaces shopping trips or increases demand, (4) the number of deliveries that can be coordinated in a single route (in this study 1 to 10), and (5) delivery timing relative to peak travel periods.
As for the factors that play a role in the level of these impacts, the researchers found that the start location of deliveries significantly impacts congestion and emissions. The case study shows that it is only possible to achieve the beneficial effects (i.e., decreases in congestion and energy use) for the case when goods are delivered from the grocery store closest to the customer. However, it is essential to note that system-wide cooperation between all grocery stores is unlikely, and this serves as an overly optimistic upper bound on the benefits of online grocery delivery adoption. Even with this unlikely cooperative system, the realizable benefits are small, especially when contrasted with the realizable negative impacts when delivering from the original grocery store.
No scenarios tested where deliveries originate from the store where customers shop achieve emissions or energy use reductions. However, congestion reductions of 3.4% are still possible if the delivery trips are shifted to off-peak hours.
Source: Samudio Lezcano, M., Harper, C. D., Nock, D., Lowry, G. V., & Michalek, J. J. (2023). Online grocery delivery: Sustainable practice, or congestion generator and environmental burden? Transportation Research Part D: Transport and Environment, 119, 103722. https://doi.org/10.1016/j.trd.2023.103722