It’s a headless robot in a driverless car.

Ford is working on a way to resolve what self-driving researchers refer to as “the last 50-foot problem.” If an autonomous delivery vehicle arrives at your house, without any humans aboard, who’s going to carry the package, grocery bags or piping-hot pizza to your doorstep? A robot, of course, could be up to the task — with no tipping necessary.

In Ford’s case, the solution is Digit, an android with two stork-like legs, arms capable of carrying a 40-pound load and a camera-encrusted torso topped by a puck-shaped laser-radar sensor. It could be the headless cousin of a battle droid from the much maligned Star Wars prequels.

The business case for driverless delivery is even more compelling than robotaxis — and potentially easier to execute. For one thing, there’s no need to worry about the safety of human passengers. And the rise of online shopping has turned package delivery into a huge growth area. Just ask Amazon, which spent $27bn on delivery costs last year.

Remove the human driver from the equation, and delivery costs could plunge by 60 percent or more. The benefits could be in the billions.

Ford would like to deploy Digit delivery robots as early as 2021, alongside the planned introduction of its autonomous vehicle fleets to ferry people and packages around the clock. “We’re going to have an AV fleet out there, and my goal is to get robots to be able to be there and ready at the same time,” said Craig Stephens, director of controls and automation in Ford's research and advanced engineering.

How real humans will react to this delivery android is a key part of Ford’s research, which is just getting underway and will include real-world tests inside Ford factories, and on the sidewalks of Dearborn, Michigan, and Pittsburgh. “Digit looks actually pretty friendly to me,” Stephens said. The “inoffensive” appearance is “going to be a key thing for people to be able to trust a robot.”

Digit was created by Agility Robotics, a startup with fewer than 30 people based in Albany, Oregon. Chief Technology Office Jonathan Hurst said he hasn't seen anyone react negatively when meeting Digit or a forbearer that lacked a torso and was simply a pair of piston-like legs attached to a motorized midsection. The robots have been allowed out on the town.

“I have a lot of people ask us, ‘Could this be perceived as creepy?’” Hurst said. “There is a small subset of people who stay far back,” he said, “and whip out their smartphone and starting taking video.”

While the design is likely to evolve, Hurst doesn't see a need to give Ford’s delivery robot a head. In fact, he wonders if that might freak people out more. “If it looks very close to an animal or a human but is not quite there, then immediately people are revolted by it,” Hurst said. “And we didn't physically need a head up there for our current perception needs.”

Others are tinkering with delivery robots, not all of which are humanoid. Anybotics and German auto-parts giant Continental demonstrated a robotic delivery dog concept at the Consumer Electronics Show this year. Segway has shown a rolling delivery device that looks like a mobile office copier, and FedEx is testing a boxy rolling bot that can climb stairs and carry up to 100 pounds. Starship Robots, which look like squat storm troopers with six wheels, are deployed in several cities around the world, according to the startup based in San Francisco and Estonia. And Postmates, which is researching autonomous grocery-getting with Ford, has a cute delivery robot known as Serve with googly eyes like Pixar's Wall-E, along with four oversize wheels.

Ford is worried that wheeled robot couriers would be blocked by front-porch steps found outside most homes in America. Digit, by comparison, can climb steps and raise its arms to catch itself in a fall. Its tiny feet, soled in corrugated rubber, can traverse concrete, grass, wood, and gravel.

Ford’s decision to go with two legs, instead of wheels, came with help from researchers at the University of Michigan. “Our world is designed for bipedals — us,” Stephens said. “So there's an inherent attractiveness to a bipedal robot.”

Another advantage is Digit’s lightweight design. Rather than outfit it with a full array of sensors and processors, which would push its bulk past 100 pounds, Digit gets most of its computing power from Ford’s self-driving vehicle. The same sensors that allow an autonomous car to navigate will be used to scan the path to the door and beam the route to the robot.

Once Digit has left the package on the porch or handed it to the recipient, it walks back to the delivery van, folds itself into a compact square, and slides into a drawer that serves as a docking station. The process looks like something out of a Transformers movie.

The suburban-porch scenario — “up the garden path to the front door,” as Stephens puts it — won’t be the only use case. Ford and Agility plan to test urban scenarios that involve gaining access to apartment buildings without the help of a doorman.

At first, however, there will be a role for human helpers. “We're not going to be deploying them by the thousands and replacing all people who do the job right away,” Hurst said.

For Ford, which specializes in commercial vehicles, driverless delivery has huge potential. The automaker has pegged the potential value of the market for robot ride-hailing and driverless delivery at $332bn. 

“The business opportunity is large,” Stephens said. “Robots are going to be necessary.”