Taking a similar approach is the team at LastMileRobotics, who is building a robotic courier based on a tried-and-true methods of the good ol' fashioned bike messenger.

Taking a two-wheeled approach to autonomous delivery could offer the same traffic-avoiding, cost-saving benefits of other concepts, such as those from the aforementioned Starship Technologies and airborne variants from Amazon and Flirtey. But the so-called TWILL bots (two-wheels in line locomotion) would be skinny and agile enough to roll up to your door. They could also boast a bigger range than drones, and lessen the risk of collisions with pedestrians and other vehicles. 

"TWILL bots stand tall, on the scale of cars," LastMileRobotics co-founder Chris Tacklind explains to New Atlas. "This allows them to be seen as just another vehicle. But they are skinny, so they don't take up a lane of traffic. The big wheels allow them to traverse large cracks and even curbs. Their agility allows them to navigate pretty much anywhere people walk."