Self Driving Car?

A Mercedes-Benz magazine ad this summer described a new sedan as a “self-driving car from a very self-driven company.” On television, the Daimler AGluxury brand showed a prototype autonomous car with passengers facing one another before cutting to a current vehicle with limited automatic steering.

“Is the world truly ready for a vehicle that can drive itself?” asked the television commercial’s narrator, adding that the future had arrived, ready or not, with a “concept car that is already a reality.”

But there was a problem: The E-Class sedan both ads portrayed isn’t a self-driving car. Rather, it features technologies, such as Drive Pilot, that can initiate a lane change by activating the turn signal, and Active Brake Assist, which warns of an imminent collision and automatically brakes if the driver fails to act.                                                                         Mercedes-Benz pulled the television ad in late July in part to “avoid any potential confusion,” a company spokeswoman said. The move came soon after consumer advocates wrote the head of the Federal Trade Commission complaining that the commercial incorrectly portrayed a fully driverless car. Mercedes-Benz already had removed the “self-driving car” reference from the separate print ad after the fatal crash in May of a Tesla Motors Inc. electric car that was driving itself.

Auto makers developing automated-driving features are confronting concerns they are giving short shrift to the technologies’ limitations and leaving customers with a false sense of security. Since the Tesla crash, U.S. lawmakers, safety advocates and others have begun homing in on how car companies describe their autonomous-driving systems.

“These companies are in an arms race to get the technology out there and demonstrate they have superior engineering,” said Mike Nelson, a lawyer at Sutherland Asbill & Brennan LLP focused on liabilities stemming from automated driving. “For the manufacturers, they’re all exposed on duties to warn and consumer-protection laws for falsely advertising capabilities. There is a lot of potential for misuses and misunderstanding.”

Consumer Reports this summer said Tesla should stop referring to its automated-driving system as “Autopilot,” calling the label misleading and potentially dangerous since the Silicon Valley company’s vehicles aren’t fully driverless.

Tesla, which kept the Autopilot name and warns drivers the system doesn’t render vehicles autonomous, said it “is constantly introducing enhancements, proven over millions of miles of internal testing, to ensure that drivers supported by Autopilot remain safer than those operating without assistance.”

Tesla added it would “continue to develop, validate, and release those enhancements as the technology grows.” At the end of August, the company’s chief executive, Elon Musk, teased on Twitter that “major improvements to Autopilot [are] coming…primarily through advanced-processing of radar signals.”

Car makers and regulators say technologies such as automatic emergency braking, adaptive cruise control and assisted steering offer safety benefits andthe potential to cut traffic fatalities that exceeded 35,000 in 2015 in the U.S. largely because of human error.

But customers remain skeptical, expressing strong desires for systems allowing them to retake control while being assured the technologies are flawless and safe, according to a survey conducted by AlixPartners LLP, a turnaround and consulting firm that advises auto makers.

Some customers concede placing outsize confidence in the technology despite fine print and other warnings from manufacturers. But even the most advanced systems available in dealer showrooms require drivers to remain engaged behind the wheel, rather than depend on computers to perform all driving functions.

The Mercedes-Benz television ad was already set to be replaced, but the auto maker retired it sooner “given the claim that consumers could confuse the autonomous driving capability of the…concept car with the driver assistance systems of our new E-Class,” a company spokeswoman said. The manufacturer all along stressed drivers should stay engaged, she said, adding the vehicle isn’t autonomous, “and we are not positioning it as such.”

An FTC spokesman confirmed that the agency received the letter highlighting the ad from groups including Consumers Union, the policy arm of Consumer Reports, and declined to comment further.

Presenting semiautonomous driving technologies concisely with all their breakthroughs and limitations is a challenge for auto makers competing to showcase systems, said Mark Wakefield, an AlixPartners managing director who advises car companies. “Describing what it does and finding one to three word descriptors for it is tough,” he said. Whatever the systems’ capabilities, fully driverless cars remain years away, he said. Cars for sale now can sometimes steer, accelerate and brake on their own, he said.

Google parent Alphabet Inc. is testing driverless cars that don’t require human interaction, but the vehicles aren’t dotting showrooms.

Volvo Car Corp. offers Pilot Assist on some cars, part of a group of features dubbed Intellisafe. General Motors Co. is developing a Super Cruise automated-driving system for Cadillacs, though the rollout was delayed.

In a July letter, Senate Commerce Committee Chairman John Thune, a South Dakota Republican, told Tesla’s Mr. Musk it was “essential to use lessons learned from” the fatal crash in Florida involving Autopilot “to improve safety technologies, ensure they perform as advertised, and make certain that consumers are properly educated about their use.”

In response, Tesla in late July told congressional staff that the benefits of automated vehicle systems outweigh the risks, said a person familiar with the meeting. Tesla representatives added that cross-traffic conditions such as those involved in the May fatal crash are a “heightened challenge” for automated-driving systems and that motorists need to exercise caution.

Automatic emergency braking sensors failed to detect the white side of a tractor trailer against a bright sky when it turned in front of a Tesla Model S, so the car failed to brake and collided with the truck, according to Tesla. Mr. Musk has said he plans to forge ahead updating Autopilot and further educating customers on its capabilities and limitations.

While proclaiming the system the most advanced on the road, Tesla warns drivers it doesn’t render vehicles fully driverless and motorists must remain engaged behind the wheel.