Uber has unveiled plans to trial autonomous'sidewalk robots' to deliver food to people's doorsteps. The US ride-hailing giant announced the idea as part of a raft of new features and services for its customers. These included an option for those in certain cities to specifically request a ride in an electric car, which Uber said was part of its global commitment to becoming a zero-emissions mobility platform by 2040. Comfort Electric is now available in Los Angeles, San Francisco, San Diego and Dubai, with more cities to come soon. The sidewalk robot concept is one of two autonomous delivery pilot programs being trialled in California.

Earlier this year six Amazon Scout delivery robots rolled out in a pilot program in Snohomish County, Wash. The boxy bots, which resemble six-wheeled ice chests, carry meals, groceries and packages to homes and offices in this region just north of Seattle. They join a small-but-growing number of automated couriers trundling down the sidewalks of London, Beijing and other cities and communities worldwide. These machines must run a gauntlet of pedestrian legs, nosy dogs and cracked pavement. Which raises the question: Why are companies investing in delivery bots at all?