Mr. Krüger added that the Tesla crash was “really very sad” and said BMW would need “the next few years” to perfect its autonomous driving system. “Today the technologies are not ready for serious production,” he said.
The world’s largest carmaker, Toyota, is a notable holdout in the rush toward completely autonomous cars. Last year, the company said that it would invest $1 billion in a Silicon Valley-based research effort to focus on cars that will function as “guardian angels,” saving human drivers from errors, rather than replacing them.
Tesla, which started its Autopilot feature last fall, has emphasized in discussing Mr. Brown’s death that the system isn’t intended to take over complete control of the car and that drivers must keep their hands on the steering wheel and remain alert and engaged.
The point highlights the difference in approach that separates companies working on self-driving technology.
Ford Motor, Google, Volvo and others are aiming at offering fully autonomous cars that can operate safely without human intervention at all — an approach engineers call Level 4 automated driving. Those companies are wary of semiautonomous, or Level 3, technology that can drive the car for stretches of road under certain circumstances, but requires drivers to be ready to take over.
Tesla’s Autopilot is not even a fully fledged Level 3 technology, and some experts say it is a risky approach.
“There’s a huge inherent danger and it’s well proven — the computer making a mistake and the driver not taking over quickly enough,” said Mark Wakefield, a managing director at Alix Partners, a consulting firm with a large automotive practice.
The trouble is that while semiautonomous systems like Tesla’s are guiding a car, human drivers can be lulled into feeling they are able to turn their attention away from the road. Mr. Brown, like some other Model S owners, posted videos showing the driver with no hands on the steering wheel. In one video, a driver climbs into the back seat.
Pete Cordaro, the owner of a vending machine company from Connellsville, Pa., owns a 2013 Model S that does not have Autopilot. But he drove a loaner with the feature earlier this year while his was being repaired. He loves his car and has deposits to buy two Model 3 compacts when that car is available, yet he is “on the fence” about getting Autopilot.
While the technology “was the greatest thing” on closed highways like the Pennsylvania Turnpike, it could become confused in more complicated environments like construction zones, Mr. Cordaro said.
“My experience is it’s really not completely safe except in limited-access highways,” he said. “It gives you a false sense of security. You get comfortable and think you can take your hands off the wheel but you really can’t. It should be called Auto-assist, instead of Autopilot, because that’s all it is.”
Even Amnon Shashua, an executive whose technology is part of Tesla’s self-driving feature, said on Friday that he did not think self-driving’s time had yet come.
Mr. Shashua is co-founder and chairman of Mobileye, an Israeli company that makes camera and sensing technology. According to the Tesla website, Tesla uses Mobileye components but developed the self-driving system in the Model S itself.
Mobileye, along with the chip maker Intel, is at work in a partnership with BMW on the self-driving car that the German automaker described in Munich on Friday that is supposed to be available in 2021.
Mr. Shashua suggested that self-driving technology was close, but still not quite ready for actual use without human drivers remaining engaged.
“Five years is a very short time,” Mr. Shashua said. “On the other hand, it is a sufficient time to do the types of validations that are needed.”
The BMW car Mobileye is collaborating on will be capable of piloting itself on highways, but not necessarily in complex urban settings.
Automakers and technology companies still need to do “hundreds of thousands or millions of kilometers of validation and simulations” in closed testing environments to be certain the technology is safe, Mr. Shashua said.
“I think it is very important, especially given this accident and what we hear in the news, that companies are very transparent about the limitations of the system,” he said.
Although Tesla has publicly said that it has enhanced the Mobileye technology, the company has not commented on whether it has enhanced the system to protect against what the industry describes as “lateral turn across path”— the type of situation in the Florida accident.
Others in the automotive industry are working on sensor technologies meant to detect vehicles from all angles.
One approach is lidar — a system that uses rotating laser beams. Lidar is being used in the experimental autonomous vehicle being developed by BMW, as well as those by Google, Nissan and Apple. But it remains unclear whether the laser system will come down enough in price to use in mass-market cars.