The prototype has the capacity to carry a payload of 40 pounds, or roughly two bags of groceries. It will travel through neighborhoods that have been pre-mapped at high resolution and will have camera and radar to see the world around it as it travels. By not using costly Lidar sensors that are capable of detecting objects as small as a pebble hundreds of feet away and that are being used on Google’s and other autonomous vehicles, the robots will cost to less to build. It will also have speakers and microphones for communicating with any humans it might encounter.

In theory, it will topple one more obstacle to online shopping. According to Brad Templeton, a software designer based in Silicon Valley and an adviser to Starship, a low-cost delivery robot like Starship will make it possible for customers to try out or try on products while the robot waits. If they don’t like what they have purchased, the robot can then return it at almost no cost.

The system is not intended for crowded urban environments, Mr. Heinla acknowledged. Rather it is targeted for relatively affluent and uncrowded suburban neighborhoods, gated communities, assisted living facilities and campuses, where it will travel on sidewalks, programmed to mingle freely with pedestrians, bicyclists and cars.

Theft is certainly a concern, but the Starship designers point out that any thieves will have to run the risk of exposing themselves to high resolution video cameras as well as a GPS tracking system that will need to be disabled.

The biggest technical challenge will be crossing intersections. To help with this hurdle, each vehicle will have the ability to call on a remote human operator whenever it faces a navigation puzzle its autonomous software cannot solve. When it confronts a pedestrian on a sidewalk, the vehicle comes to a halt until the human passes. The Starship robot is designed to make deliveries for a cost of less than $1, which Mr. Heinla says is five to 15 times as cheap as current human-driven delivery vehicles.

Mr. Heinla, who helped develop the Kazaa file-sharing service before Skype, says his 30-person Estonian firm will start its first experimental delivery systems in Greenwich, England, and the United States next spring. Commercial service is planned for 2017. The systems will also provide environmental benefits by reducing gas-powered vehicle traffic, he said.

There are of course both practical and regulatory obstacles that need to be overcome. For example, today in the United States, only a handful of states would allow such an autonomous vehicle to travel on the sidewalk. In some cases, cities may be able to offer legal exemptions to allow the vehicles to travel on sidewalks in specific neighborhoods.