Tesla (NASDAQ: TSLA) started updating the software for its Autopilot system Thursday morning, giving thousands of drivers who own a Model S or Model X an enhanced version of its driver assistance system.

The upgrade comes amid a debate over the safety of this system, which heated up in late June after the company said a Model S owner was killed while his vehicle was in that mode. The system did not see a tractor-trailer turning in front of his Tesla vehicle, which slammed into the truck.

"It is extremely important to get this right because Tesla is really alone in the ability to drive the vehicle with the people being able to take their hands off the wheel for an extended period of time," said Jake Fisher of Consumer Reports.

Here's what Tesla's improved with its Autopilot 8.0 software:

• Tesla now incorporates the onboard radar to give the vehicles a better view of the road, traffic ahead and potential obstacles;

• Autopilot now can see two cars ahead, so Tesla vehicles will react faster when there is sudden braking on the highway;

• Autosteer now navigates highway interchanges;

• Enhanced warnings keep drivers engaged. If drivers ignore repeated warnings, the new software will disable Autosteer until drivers stop and re-engage the system.

Tesla CEO Elon Musk says Autopilot 8.0 will make his company's vehicles among the safest on the road, and likely could have prevented the accident it reported in June. Just days after he made that claim, the chairman of Mobileye (NYSE: MBLY) told Reuters that Tesla's new system is "pushing the envelope in terms of safety."

The two companies had previously worked together on developing driver assistance technology. Tesla responded by saying Mobileye's comments came after it learned the automaker would use its own technology for upcoming versions of its autopilot system.

Krishna Kalidindi, who lives in San Jose, California, and bought a Tesla Model S earlier this year, is eager to see how the new Autopilot system works. He acknowledged he's had to stay alert while using the previous version of the technology.

"The driver has to understand the limitations of it," said Kalidindi, as his Model S zipped along U.S. Highway 101 South at 65 mph in Autopilot mode. "You kind of have to know what the limits of Autopilot are. It is still not 100 percent autopilot. You still need some type of steering."

It's unclear how Tesla's new safety enhancements will impact an ongoing probe by the National Highway Traffic Safety Administration. That investigation was sparked by the fatality earlier this year.

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