Trucks filled to capacity that deliver to customers clustered in neighborhoods produced the most savings in carbon dioxide emissions.
"A lot of times people think they have to inconvenience themselves to be greener, and that actually isn't the case here," said Anne Goodchild, UW associate professor of civil and environmental engineering.
"From an environmental perspective, grocery delivery services overwhelmingly can provide emissions reductions," she added.
As companies continue to weigh the costs and benefits of offering a delivery service, Goodchild and Erica Wygonik, a UW doctoral candidate in civil and environmental engineering, looked at whether using a grocery delivery service was better for the environment, with Seattle as a test case.
In their analysis, they found delivery service trucks produced 20 to 75 percent less carbon dioxide than the corresponding personal vehicles driven to and from a grocery store.
They also discovered significant savings for companies - 80 to 90 percent less carbon dioxide emitted - if they delivered based on routes that clustered customers together, instead of catering to individual household requests for specific delivery times.
The research was funded by the Oregon Department of Transportation and published in the Journal of the Transportation Research Forum.