A new study finds that drone deliveries emit less climate-warming carbon dioxide pollution than truck deliveries in some—but not all—scenarios. Image credit: www.routexl.com / CC BY 2.0As drone delivery becomes increasingly more popular, researchers from the University of Washington are investigating what the environmental consequences of drone delivery might be compared with traditional methods of delivery—namely, trucks.

According to the study, drone use reduces carbon dioxide emissions in certain instances when measured against trucks.

Drones are more environmentally friendly, according to researchers, when they are delivering smaller packages, when they are flying shorter distances and when a delivery route has fewer recipients. However, they tend to expend more energy when carrying heavier packages in an effort to stay aloft.

Researchers believe that trucks present an environmental advantage in instances that require carrying multiple deliveries of varying shapes and sizes (all in one trip) and when they have many delivery stops along one route.

"Flight is so much more energy-intensive—getting yourself airborne takes a huge amount of effort. So I initially thought there was no way drones could compete with trucks on carbon dioxide emissions," said senior author Anne Goodchild, a UW associate professor of civil and environmental engineering. "In the end, I was amazed at how energy-efficient drones are in some contexts. Trucks compete better on heavier loads, but for really light packages, drones are awesome.”

The entire study is published in Transportation Research Part D.