Evaluating the Impacts of Density on Urban Goods Movement Externalities

Research has established a potential to reduce vehicle miles traveled (VMT) by replacing passenger travel for shopping with delivery service, and a few studies have indicated CO2 emissions can also be reduced. However, that research has mostly focused on urban locations and has not addressed criteria pollutants. This study examines the impacts of replacing passenger travel for shopping with delivery service over a broader set of externalities (VMT, CO2, NOx, and PM10) in both urban and rural communities. Three different goods movement strategies are considered in three different municipalities in King County, Washington, which vary in size, density, and distance from the metropolitan core. The research finds that delivery services can reduce VMT over passenger vehicle travel for shopping, however, the potential to reduce CO2, NOx, and PM10 emissions varies by municipality. Significant trade-offs are observed between VMT and emissions – especially between VMT and criteria pollutants.