Safety regulators have told Google that federal motor vehicle regulations could consider a computer to be the driver of a car, a decision that will help speed the development of autonomous vehicles.

The interpretation appears in a Feb. 4 letter to Google from Paul Hemmersbaugh, chief counsel for the National Highway Traffic Safety Administration. It was posted on the agency’s website.

The decision is a response to a request by the Mountain View, Calif., tech company about how provisions of the Federal Motor Vehicle Safety Standards would apply to Google’s fully autonomous motor vehicles – cars that would be controlled exclusively by a “Self-Driving System” or SDS.

“We are taking great care to embrace innovations that can boost safety and improve efficiency on our roadways. Our interpretation that the self-driving computer system of a car could, in fact, be a driver is significant,” said U.S. Transportation Secretary Anthony Foxx. “But the burden remains on self-driving car manufacturers to prove that their vehicles meet rigorous federal safety standards.”

How the agency treats these vehicles will have a broad effect on trucking and shipping.

The U.S. Patent and Trademark Office on Tuesday awarded Google a patent for a self-driving delivery truck.

NHTSA tell Google computers can be vehicle “drivers”

Sketch of Google's self-driving delivery truck system (Photo: U.S. Patent and Trademark Office)

The patent documents depict a typical delivery truck – similar to what UPS and FedEx use – with lockers on the outside. The vehicle would robotically drive to a home or office and digitally signal the recipient that their package had arrived.  The individual would walk out to the van, punch a code into the locker’s keypad and remove their package.

Other companies are working on different applications for robotic trucks.

Freightliner last year obtained a Nevada license to test its Inspiration self-driving truck on public highways. The company said the big-rig is an important step in robotic driving and will lead to technology that reduces accidents, improves fuel consumption and cuts highway congestion.

Google officials see many of the same benefits resulting from their autonomous car program.

There are 1.2 million deaths from traffic accidents worldwide annually that “could be reduced dramatically” by robotic driving, Google said. About 94 percent of accidents in the U.S. involve human error, according to federal safety regulators.

Unlike the self-driving projects of mainstream auto and truck makers, Google is developing a vehicle architecture that lacks basic features such as a steering wheel and gas and brake pedals. It envisions pod-like vehicles that robotically transport passengers to their destinations.

In reviewing whether such a vehicle architecture would meet federal safety standards, NHTSA said it will interpret “driver” in the context of Google’s design as referring to the computerized self-driving system rather than to any of the vehicle occupants.

“We agree with Google its (self-driving vehicle) SDV will not have a driver in the traditional sense that vehicles have had drivers during the last more than one hundred years,” Hemmersbaugh wrote.

He said the vehicle’s design would not provide any way for a human to take over driving.

“If no human occupant of the vehicle can actually drive the vehicle, it is more reasonable to identify the driver as whatever (as opposed to whoever) is doing the driving. In this instance, an item of motor vehicle equipment, the SDS, is actually driving the vehicle,” Hemmersbaugh said.

Google needs regulators to interpret how safety standards would apply to such a vehicle.

NHTSA notes that the rules “were drafted at a time when it was reasonable to assume that all motor vehicles would have a steering wheel, accelerator pedal, and brake pedal, almost always located at the front left seating position, and that all vehicles would be operated by a human driver.”

That means the rules required that basic features be located near the driver. But if a computer is driving the vehicle, it no longer matters where the controls for lights are or where dashboard alerts are located. NHTSA said rules will have to be rewritten to handle such situations.

The standards, for example, state that brakes “shall be activated by means of a foot control, and also that control of the parking brake shall be independent of the service brake control, and may be either a hand or foot control.”

The agency agreed with Google that the self-driving system would functionally be in compliance with braking requirements. It can electronically trigger the brakes to stop safely. Moreover, the system can be tested to prove that is in compliance with federal regulations for brake systems. But because the standards as written require the brake systems to be activated by human feet and hands, the car would not comply with the language of the rules.

Where it can, the agency will issue interpretations that will speed Google’s self-driving car project. But Hemmersbaugh said, “there are limits to the result the agency may reach in an interpretation, even if it believes that result might be sound policy.”

Some of the issues Google has broached will have to be settled through the formal and often lengthy federal rule-making process, he said.