Cathy Bussewitz

Associated Press

The nation’s largest grocery chain is leaping into the driverless delivery market, announcing Tuesday that it is now ready to bring milk, eggs and apples to some customers’ homes in a vehicle with nobody at the wheel.

Although limited to delivering within about a mile of one Arizona supermarket, it represents the latest step for industries trying to lower delivery costs of everyday items as well as those trying to launch self-driving cars on public roads.

But Tuesday’s launch also highlighted some of the many challenges that are still ahead for autonomous vehicles: The compact car didn’t drive as planned at a media demonstration and had to be pushed up a ramp and onto a truck by several men before it could deliver the first loaf of bread.

Kroger and Nuro, an autonomous vehicle company based in Mountain View, California, announced Tuesday they would begin delivering groceries in Scottsdale, Arizona, using an autonomous vehicle called the R1, which has no steering wheel and no seats for humans.

Nuro has been delivering groceries with larger, manned self-driving vehicles since August. It will be adding two of its completely unmanned R1 vehicles to that fleet, said Dave Ferguson, president and co-founder of Nuro. He said a vehicle at the demonstration didn’t drive because its battery had died.

When summoned, the R1 will travel within a one-mile radius of the Fry’s Food grocery store just east of the Phoenix Zoo at speeds up to 25 miles per hour on residential roads, but stay clear of main roads or highways, according to Pam Giannonatti, corporate affairs manager at Cincinnati-based Kroger Co.’s Fry’s division.

Customers, after placing an order on their smartphone or laptop, will get a text message when the groceries are on their way. Another message will alert them when the grocery delivery is curbside. Once the vehicle arrives, the customer will receive a punch code to open the doors of the vehicle, Giannonatti said.

Customers will pay a flat fee of $5.95 and can request same-day or next-day delivery.

The unmanned delivery vehicles will be followed by a “shadow car,” which will be driven by a human with the ability to stop or control it. The “chase car” is being used in the early stages of the program out of an abundance of caution and will be eventually phased out, Ferguson said.

“This is not yet at the point where in any way it’s economically better than just sending someone out in a car to deliver your groceries,” said Bryant Walker Smith, a professor at the University of South Carolina, who teaches about emerging technologies. “It will probably cost much more, and the range is minimal, and there are lots of ways it would not be a true, commercial-scale, viable deployment, but it’s an important step on that path.”

Attempts to deploy fully autonomous vehicles on public streets have been limited by technological hurdles, as well as human apprehension.

Uber pulled its self-driving cars out of Arizona this year following the death in March of woman who was run over by one of the ride-hailing service’s robotic vehicles while she crossed a darkened street in a Phoenix suburb. It was the first death involving a fully autonomous vehicle.

That vehicle had a backup driver at the wheel.

Waymo, a self-driving car spinoff from a Google project, has been offering free rides in robotic vehicles with no human backup driver as part of a test program in the Phoenix area for the past year. Earlier this month, Waymo launched a ride-hailing service available to about 200 people that will have a human behind the wheel to take control in case something goes awry.

Giannonatti said safety is paramount in this next step of autonomous vehicle technology.

Because the R1 delivery vehicle is unmanned, it was designed to prioritize safety of other drivers or pedestrians without trading off the safety or comfort of a driver or passengers, Ferguson said.

The delivery vehicle’s size – half the width of a Toyota Corolla – also helps prevent collisions with pedestrians because there’s more buffer room, Ferguson said.

Kroger has been working hard to boost online sales in order to keep up with Walmart and Amazon, which bought grocer Whole Foods last year.

Tuesday’s announcement puts Kroger ahead of Walmart and Amazon in self-driving deliveries, says Jon Reily, vice president of commerce strategy at Publicis.Sapient.

“But ultimately,” he says, “there are so many challenges with autonomous vehicles” to make it a reality nationwide.

Among them: state laws and weather. Arizona’s laws have been friendlier to self-driving vehicles, and the weather in Scottsdale is more predictable than in other parts of the country.