During the last two years, self-driving car technology has seen rapid development, spurred billions of dollars of investment and offered the potential to shake up the trillion-dollar worldwide auto industry to an almost unprecedented level.

Central to the promise that self-driving cars offers is the huge increase in auto safety. With computers that know the roads and traffic patterns, and can see and sense other cars and their real-time driving patterns, cars guided by software have the potential to drastically decrease the 38,000 deaths and 4.4 million injuries sustained on American roadways in 2015.

But as recent headlines have shown, self-driving cars — especially at this early stage in their development — are not a panacea for traffic accidents.

Most companies developing self-driving auto technology, such as tech giants like Google and major manufacturers like Ford and GM, are testing such vehicles under controlled, highly supervised conditions. Those automotive companies likely won't have self-driving production cars on the market until the start of the next decade, if not later than that.

However, electric-car maker Tesla has chosen a different route for its self-driving program. Starting in August 2015 for select testers on its Model S sedans (and that October for all other Model S drivers), Tesla offered its "public beta" Autopilot as a software download. The technology was also eventually rolled out to Tesla's Model X sport-utility vehicles, which also debuted last fall.

It should be noted the Autopilot function is by no means the default mode in Tesla's cars, and Autopilot is justly referred to as "semi-autonomous" in the media, as it encourages, reminds and eventually requires the driver to put his or her hands on the steering wheel, and turns off when a driver inputs steering.

Yet, despite these fail-safes, a fatal accident in a Tesla Model S with Autopilot activated occurred May 7 in Williston, Florida, taking the life of 40-year-old technology enthusiast Joshua Brown, who uploaded many videos of his Model S on Autopilot on his YouTube channel before passing away.

Additionally, there are reports that a nonfatal rollover accident on the Pennsylvania Turnpike in a Model X occurred July 1 with the vehicle in Autopilot mode. Tesla has not confirmed the use of Autopilot, and the National Highway Traffic Safety Administration (NHTSA) is investigating both the fatal and nonfatal accidents.

Tesla confirmed the fatal wreck June 30 in a blog post — the first known fatality in a vehicle operating with autonomous technology.

In that blog, Tesla touted safety of its technology, saying, "This is the first known fatality in just over 130 million miles where Autopilot was activated. Among all vehicles in the U.S., there is a fatality every 94 million miles. Worldwide, there is a fatality approximately every 60 million miles."

Still, Tesla is coming under fire for having rolled out the technology more like a smartphone app, and without comprehensive testing like the other car companies.

"Cars are not toys and to launch a beta version of software with safety risks is not the way a company should care about the life of human beings. Just putting a sticker on it saying 'customer is responsible' is a nightmare," Ferdinand Dudenhöffer of Centre of Automotive Research at the University of Duisburg-Essen in Germany told Olivia Solon of The Guardian.

Tesla may end up being held liable for Brown's death if it can be shown the Autopilot software was insufficient for proper driving conditions. It has been reported that Brown's death occurred because the computer did not spot a white semi truck on a bright day, causing the Model S to not stop as it should have, and as human eyes likely would have.

While the news of the Autopilot death immediately raises questions and federal inquiry as to how equipped Tesla's technology is for American roadways, the overarching momentum of self-driving technology doesn't appear to be halted.

BMW, only a day after Tesla went public with the news of Brown's death, announced its plans to bring self-driving cars to the market by 2021. In order to achieve that goal, it may have to make even more sure its technology is at its safest possible level.