Washington, DC CNN  — 

Ben Morris bought his Tesla in 2020 believing that it would drive itself one day. Now he says he would settle for continuing to feel safe using its cruise control.

Morris is one of hundreds of Tesla owners claiming that the automaker’s cruise control has deteriorated and turned dangerous in the last year on some models. They’ve filed complaints with the National Highway Traffic Safety Administration, which opened an investigation last month.

In the complaints, the owners say they’ve nearly been rear-ended after their vehicles brake unexpectedly, which they call “phantom braking.” Many say they have stopped using cruise control because they’re afraid it will trigger a crash. Some drivers have said on social media and in interviews with CNN Business that the cruise control issues have them questioning when or if Tesla will deliver self-driving vehicles, which tech and auto companies have promised for years.

Tesla CEO Elon Musk said in 2015, 2016, 2017, 2018, 2019 and 2020 that self-driving Teslas were probably either a year or two away. More recently, he’s said that self-driving will be a reality this year, even as the automaker continues to describe its more basic driver-assist feature “traffic-aware cruise control,” as a beta feature almost seven years after its launch. (Beta is Silicon Valley lingo for an unfinished and imperfect product.)

“They’re burning up a lot of good will with not being transparent,” Morris told CNN Business. “People are starting to realize, ‘My car may actually never drive itself.’”

Tesla did not respond to a request for comment.

“The ultimate gadget”

Morris, a software engineer in Indiana, describes Teslas as “the ultimate gadget.” He grew excited in recent years after hearing Musk’s talk of Teslas driving themselves.

“I wanted to make sure I got a Tesla with all the bells and whistles, and ‘full self-driving’ was one of them,” Morris said, referring to a Tesla driver-assist feature that is expected to eventually be able to drive the vehicle. For now, “full self-driving” requires an attentive driver behind the wheel, and has only been released to a limited number of Tesla drivers, who have described significant issues.

Morris said he was happy with his first Tesla, a 2016 Model S. When its warranty ended, he purchased the Model X he still owns today. Then almost a year ago, Morris surprised his wife on Mother’s Day with a Tesla Model Y.

Morris said shortly before the SUV arrived, Tesla messaged him to say that the radar was being phased out of the automaker’s cruise control. Most automakers rely on radar for adaptive cruise control, which speeds up and slows down the vehicle slightly to keep pace with a vehicle in front of it. (Tesla calls its adaptive cruise control, “traffic-aware cruise control.”)

Most autonomous vehicle experts favor sensor fusion, in which camera and radar data are combined to sense a car’s surroundings.

“It’s like pairing one A student with another A student,” said Steven Hong, vice president of radar technology at Ambarella, which is combining radar and camera in a driver-assist system. “Put them together and you’ll get an A+ on your perception project as they cover each other’s weaknesses.”

Cameras can struggle in poor lighting conditions whereas radar functions even if there is rain, fog, or mud covering the vehicle, he said.

Trouble for Morris began not long after the Model Y arrived, he said. The car often braked unexpectedly as his wife commuted on a two-lane road in rural Indiana. According to a review by CNN Business, more than 120 drivers have filed complaints with NHTSA describing unexpected braking on two-lane roads.

“Cruise control is completely unusable on two-lane roads,” wrote one person in February who said they were from Des Moines, Iowa.

As his wife drove on the two-lane road last fall, her Model Y slammed on its brakes so hard that his children’s empty booster seats in the second row flew forward and crashed into the front seats, he said.

A concerned Morris reached out to Tesla. The automaker told Morris, according to screenshots shared with CNN Business, that there was no hardware failure.

“Because there is no need for service we will close out this appointment,” the automaker wrote. It also explained that cruise control is a beta feature.

“As far as I understand cruise control should not be a beta feature,” he replied.

Then he checked his owner’s manual, which calls traffic-aware cruise control a beta feature. Tesla introduced the feature in 2015 and based on a review of Tesla owner’s manuals, it appears that the automaker started labeling it a “beta” feature in 2018.

Morris filed a complaint with the US government in November, noting that “we don’t accept beta seatbelts or beta tires.”

Thirty other Tesla owners filing complaints of unexpected braking say that Tesla has either canceled service appointments or told them there is nothing they can do, according to a CNN Business review of complaints.

Cruising along

Tesla introduced “traffic-aware cruise control” to its vehicles in 2015. Previously, Teslas included a basic cruise control that held a consistent speed without requiring that drivers keep their foot on the accelerator, according to a review of Tesla owners’ manuals.

Traffic-aware cruise control initially relied on a radar and camera to sense the road ahead, and Tesla warned of the feature’s limitations.

“Traffic-Aware Cruise Control may occasionally brake Model S when not required,” cautioned the 2015 Model S owner’s manual. A similar warning remains in the latest Tesla owners’ manuals.

Other automakers also warned that adaptive cruise control has shortcomings. Ford, for example, cautions that its system may brake unexpectedly. It recommends against using adaptive cruise control on winding roads, as do General Motors, Toyota, Honda and Tesla, according to a review of owner’s manuals.

Morris, the Tesla owner, also drives a Ford F-150 with adaptive cruise control. He said he’s never experienced unexpected braking with it. He said his Model X, which has a radar, does not brake unexpectedly on the same roads that his wife’s radar-less Tesla struggled with.

But the use of radar does not prevent all unexpected braking issues.

NHTSA opened an investigation last month into unexpected braking of 2017-2019 Honda CR-Vs and 2018-19 Honda Accords following 278 complaints. Honda’s system relies on radar.

Tesla owners have long described on social media episodes of phantom braking on radar-equipped vehicles, generally slowing the car about 5 mph, not as severe as what’s been reported to NHTSA.

Morris has since traded in the Model Y for Ford’s Mustang Mach-E. The infotainment system is “kind of clunky” and can’t match Tesla’s, he said, but his unexpected braking worries are gone. The F-150 and Mustang’s system relies on a radar and camera.

Morris said he would have kept the Model Y if it had offered a dumbed-down cruise control that held a constant speed. He still loves his Model X, for now.

“If they ever disable my radar,” Morris said. “I’m going to probably get rid of it, too.”