(Bloomberg) — U.S. crash investigators faulted Tesla Inc.’s Autopilot system and the driver’s distraction by a mobile device for a fatal accident in 2018 and called on Apple Inc. and other mobile phone makers to do more to keep motorists’ attention on the road.

Tesla was heavily criticized for not doing enough to keep drivers from using its driver-assist function inappropriately. American regulators, which have guidelines but no firm rules for the emerging automated driving systems, were also attacked by the safety board.

“It’s time to stop enabling drivers in any partially automated vehicle to pretend that they have driverless cars, because they don’t have driverless cars,” National Transportation Safety Board Chairman Robert Sumwalt said.

The hearing was a searing critique of how Tesla and other carmakers have introduced new technologies that automate aspects of driving but still require constant human supervision, and of the National Highway Traffic Safety Administration’s light-touch approach to regulating the safety of those systems.

Even though the Tesla SUV in the 2018 crash in northern California had previously veered toward a concrete barrier, the driver, an Apple employee, allowed the semi-autonomous system to essentially steer itself as it passed that same location and moved toward a highway barrier, the NTSB concluded. The driver failed to intervene because he was distracted, likely because he was playing a game on a mobile phone provided by his company, which lacked a policy prohibiting employees from using devices while driving, the NTSB found.

The NTSB has for years issued warnings about distracted driving and its deadly toll on the roadways. During the hearing, it called on Apple and other mobile phone manufacturers to develop protections to prevent misuse of electronic devices behind the wheel as a default setting.

The agency also urged the NHTSA to conduct a fresh evaluation of Autopilot and take enforcement action if necessary if the agency finds defects.

“We urge Tesla to continue to work on improving their Autopilot technology and for NHTSA to fulfill its oversight responsibility to ensure that corrective action is taken when necessary,” Sumwalt said.

The death of 38-year-old Apple engineer Walter Huang in March 2018 in Silicon Valley prompted the NTSB to issue its strongest findings to date on safety risks posed by automated driving systems and driver distraction by mobile devices.

“Limitations within the Autopilot system caused the SUV to veer towards the area with a concrete barrier that it ultimately struck, which the driver didn’t attempt to stop due to distraction,” the board found.

NTSB recommended that both mobile device manufacturers such as Apple, Google and Samsung Electronics Co., as well as employers more broadly, do more to combat distracted driving.

Mobile phone manufacturers should lock out features on the devices as a default setting, rather than as an optional feature that must be activated manually, the NTSB said. Employers should adopt policies banning non-emergency mobile phone use by employees when behind the wheel.

The NTSB posted a document on Monday in its public record on the crash showing Apple didn’t have a policy on distracted driving.

“I checked around with various groups and we do not have a policy related to phone use and driving,” wrote an Apple representative in an email response to the NTSB, which was posted to the safety board’s public investigative files on Monday.

An Apple spokesman said the company expects its employees to follow the law. Tesla didn’t respond to a request for comment but has said it has updated Autopilot in part to issue more frequent warnings to inattentive drivers and that its research shows drivers are safer using the system than not. Tesla has also repeatedly stressed that drivers must pay attention while using Autopilot.

The combination of growing mobile device use in semi-autonomous cars, in which drivers can take their eyes off the road for long periods, is a combustible mix, said NTSB Vice Chairman Bruce Landsberg.

“What this crash illustrates is not only do we have the old kind of distraction” Lansberg said. Partly-automated driving systems present “yet another kind, which is the automation complacency of the system almost kind of always works, except when it doesn’t.”

NTSB board member Jennifer Homendy criticized the NHTSA for issuing a recent statement saying it was trying to limit regulations to make cars more affordable.

“What we should not do is lower the bar on safety,” Homendy said. “That shouldn’t even be considered for an agency that has the word safety in its name.”

NHTSA said in a statement it was aware of the NTSB’s report and would review it. It also said distracted driving remains a concern and that drivers of every motor vehicle available currently on sale are required to remain in control at all times.

It is also conducting more than a dozen of its own investigations into Tesla crashes linked to its semi-autonomous system known as Autopilot. Tesla is one of the leading developers of automated driving technology.

Warnings to Driver

Huang’s Tesla struck the concrete highway barrier at about 70 miles (113 kilometers) per hour. His hands weren’t detected on the steering wheel for about one-third of the drive and the car twice issued automated warnings to him.

A protective barrier on the highway designed to reduce the crash impact wasn’t in place, the NTSB found.

In addition, Tesla and government agencies haven’t bothered to respond to NTSB’s recommendations related to an earlier, similar crash.

Smartphone manufacturers and software developers have taken some steps to address distracted driving. Apple’s iPhone, for example, has a feature to block text message and other notifications when driving that a user can activate in the phone’s settings.

“The challenge is that they’re all passive systems. They require you as the owner of the phone to take that action, and many won’t or don’t because they don’t have to,” said Kelly Nantel, vice president of roadway safety at the National Safety Council.

While the safety board stopped short of concluding that NHTSA’s lack of actions were part of the cause of the crash, it found that the regulator hadn’t done enough to set safety standards and called its approach to semi-automated vehicles “misguided.”

Separately, the NTSB is prepared to cite the highway-safety regulator’s actions in another fatal Tesla crash as a contributing factor.

In a March 2019 crash in Delray Beach, Florida, a Tesla drove into the side of a truck without braking, killing the driver. The conclusions of the investigation haven’t been published, but were read by Homendy during Tuesday’s meeting.