Back in July, it was reported that Mobileye - the Israeli startup that supplied the image-recognition hardware used in Tesla's Autopilot technology - was parting ways with Elon Musk's company. Yesterday, co-founder Amnon Shashua revealed the separation was because the automobile maker is "pushing the envelope in terms of safety."

The two companies had been partners for years, but Mobileye ended the relationship following a fatal crash last May where the autopilot system failed to recognize a truck crossing the highway laterally. Tesla later wrote in a blog post that the accident happened because "neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied."

Speaking in an interview with Reuters, Sashua said the system "is not designed to cover all possible crash situations in a safe manner."

"No matter how you spin it, [Autopilot] is not designed for that. It is a driver assistance system and not a driverless system," he added.

The safety of the autopilot feature, which helps drivers stay in lanes and steer on highways, has come under increased scrutiny after it was blamed for several accidents. Recent reports from China claim that the first fatal crash involving the system may have taken place in the Asian country back in January.

Responding to Sashua's accusations, a Tesla spokeswoman said the company has never described Autopilot as an autonomous technology or a self-driving car.

"Since the release of Autopilot, we've continuously educated customers on the use of the features, reminding them that they're responsible to keep their hands on the wheel and remain alert and present when using Autopilot. Drivers must be prepared to take control at all times."

Not long after the Autopilot system launched, a number of YouTube videos appeared featuring Tesla owners traveling down highways in the vehicles with their hands off the wheel. One showed a person sitting in the back seat of the car as it hit 51 mph on a Dutch road.

Mobileye's criticism comes after Musk's announcement Sunday that an update to Autopilot will supposedly make it safer to use. The system will rely more on Tesla's integrate radar system, and should drivers continue ignoring warning to keep their hands on the wheel, Autopilot will be turned off until the car is parked. Musk said it was "very likely" that this new version would have prevented the fatal crash in May.