Delivery robot company Nuro won the first federal safety approval for a purpose-built self-driving vehicle, advancing the young company’s plans to cart groceries around neighborhoods and reaching a milestone for the autonomous vehicle industry.

The approval indicates that federal regulators at the Department of Transportation think specially built robot cars can safely take to the roads without matching all the design standards for regular vehicles.

Nuro says it plans to begin testing soon in Houston.

Many of the existing rules are designed to ensure that the person at the wheel remains safely in control. But Nuro’s vehicle, which it calls R2, won’t need mirrors or a windshield.

Transportation Secretary Elaine Chao said that in the context of a self-driving delivery vehicle, those features “no longer make sense.”

The federal approval also carries strict limits. It’s good for only two years, and Nuro’s lightweight robots won’t carry passengers, won’t travel faster than 25 mph, and production will be capped at 5,000 vehicles.

But it indicates that federal regulators, who have been grappling with how to allow the autonomous-vehicle industry to continue experimenting without sacrificing public safety, have found a path toward the next generation of vehicles.

The Trump administration has adopted a largely hands-off policy, wary of stifling innovation, but has faced criticism from safety advocates and some lawmakers that it’s leaving too much up to industry.

In its written ruling, the National Highway Traffic Safety Administration noted that it wasn’t required to determine the competence level of Nuro’s robotic driver. But recognizing the vehicle’s novelty, the agency said it would require the company to share information with regulators every 90 days, turn over detailed data after a crash, hold quarterly meetings with officials, and engage with communities where it wants to deploy the R2.

The slender robot is much smaller than a regular car, with large doors that open upward to reveal its cargo compartment.

Houston customers will be able to place an order for delivery from Domino’s Pizza, Kroger or Walmart. A robot will deliver pizza or groceries to a designated spot and the customer will enter a code to unlock the robot and retrieve purchases. Kroger plans to charge a $5.95 fee; Walmart and Domino’s haven’t determined their fees.

Dave Ferguson, one of Nuro’s founders, wrote in a blog post that the R2 is designed to protect pedestrians and programmed to drive courteously, so it’s positioned to become a trustworthy and “socially responsible” user of neighborhood streets.

There is considerable excitement among government officials and industry leaders about the potential for self-driving vehicles to transform the nation’s transportation system. But the practical questions of how to get the vehicles to work have been tougher than many expected, and regulators have grappled with their role.

The uncertainty has led some experts to predict that low-speed vehicles like Nuro’s, designed for shorter trips around neighborhoods, will be the first to enter wide use.

At a planned development in Reston, shuttle company Optimus Ride is experimenting with low-speed shuttles. The company said recently that demand for its service is strong and that it has increased the number of vehicles it is running.

Ferguson wrote that the government “has shown that safety and innovation can advance together, and that they will act to address regulations that stand in the way.”

“Moving forward, we must modernize the existing regulations that never envisioned a vehicle without a driver or occupants, and everyone in the industry must work to ensure self-driving technology is tested and deployed in the safest possible vehicles,” he wrote.

Ferguson and Jiajun Zhu, who both previously worked at Google’s self-driving car company, founded Nuro in 2016. The company began testing a version of its vehicle in Arizona in 2018, doing grocery deliveries for Kroger.

The company said exemptions from the existing standards have allowed it to create a vehicle that is safer, describing a front panel designed to cause less harm to a pedestrian than a windshield would in a crash.

And while some of the design changes might seem obvious, Nuro said it also received approval to have vehicle cameras activated at all times. The rules typically do not allow that, for fear of distracting a human driver.

Vehicles such as golf carts and neighborhood buggies don’t have to comply with the full set of car safety standards. That made Nuro’s NHTSA petition more straightforward, as the company sought just three exemptions.

But automakers’ and tech firms’ ultimate ambition is to create a driverless vehicle that would replace today’s passenger cars and SUVs.

Cruise, which is backed by General Motors and Honda, last month unveiled its proposed design for an autonomous passenger vehicle called the Origin. The company ultimately wants to operate the vehicle as a ride service, saying that removing the driver creates more space for passengers and will cut costs.

GM has applied for a safety standards exemption similar to Nuro’s for a precursor vehicle to the Origin. That application, which is much more complicated, is pending, and a spokesman for NHTSA recently said there was no update on it.

In its ruling on Nuro’s petition, NHTSA said that in the case of a company seeking to be exempted from many more safety rules, the agency could decide that it needed to review how well the self-driving system itself worked.

Dan Ammann, Cruise’s chief executive, said in an interview last month that his company is working closely with the federal government.

“They’re well aware of what we’re up to, unsurprisingly,” Ammann said. “Certainly at a conceptual level, and I think deeper down than that, there’s a very forward-thinking mind-set and approach in terms of what we’re seeing at the federal level.”