Tesla's Autopilot semi-autonomous feature will get a major update Wednesday.

In a tweet on Friday, Elon Musk, Tesla's CEO, said the automaker planned to roll out the update on 21 September. Musk detailed the upcoming software changes Sunday in a blog post, where he said Autopilot will now rely mostly on radar and not just cameras, which will help its electric vehicle to "see" what's going on around it and avoid collisions like the one that killed a driver in May.

"After careful consideration, we now believe [radar] can be used as a primary control sensor without requiring the camera to confirm visual image recognition," wrote Musk, explaining the update will include more data points from the radar to create a 3D picture of the car’s surroundings. Tesla first added radar to its vehicles in 2014 to aid its camera systems.

Beyond giving radar a greater role, Tesla's upcoming Autopilot update will ensure drivers stay alert when using Autopilot. If a driver ignores warnings to take the wheel, he or she will need to park and restart to use Autopilot again. Musk said on Sunday these changes will make Tesla vehicles “by far the safest on the road", though he also warned they won't mean "perfect safety".

Tesla's Autopilot update is likely in response to that fatal crash in Florida. It involved a Tesla Model S driver using Autopilot. Although the feature was engaged, the sedan hit a white truck. The National Highway Traffic Safety Administration is investigating the crash, presumably to look into why Autopilot reportedly failed to differentiate the truck from the bright sky.

Stay tuned to Pocket-lint's Tesla hub for the latest news.