Tesla began rolling out Full Self-Driving (Supervised) version 14.3.9, also labeled software version 2026.27.5, to eligible cars in North America starting September 6, 2026, according to release notes published by Not a Tesla App. As with past FSD releases, the update is going out gradually rather than to every car at once, so owners may not see it appear immediately.
A new safety feature that can take the wheel
The headline addition is a feature Tesla calls Automatic Collision Evasion. According to Electrek’s report on the feature, it lets FSD Supervised briefly take over steering, braking, and acceleration during manual driving if the car detects an imminent frontal collision that Automatic Emergency Braking alone may not stop, or if it senses the driver is severely inattentive. Tesla describes it as a last-resort function, not a replacement for an attentive driver, and Electrek notes the car intervenes only below highway speeds of about 85 mph. Drivers can override the maneuver with firm, deliberate steering force; tapping the brake alone does not cancel it.
Neural network and driving-behavior changes
Beyond the new safety feature, Tesla’s official release notes for 2026.27.5 describe an upgraded reinforcement-learning training stage for the FSD neural network, a rewritten AI compiler and runtime that Tesla says produces a 20% faster reaction time, and an updated vision encoder aimed at rare and low-visibility scenarios. The notes also list behavior tweaks such as reduced unnecessary lane biasing and tailgating, improved handling at complex intersections with compound traffic lights, and a unified model shared across Summon, FSD, and Robotaxi.
One driver’s reaction on video
Recharge and Roam posted this reaction on September 6, 2026:
The video shows one driver’s personal experience testing the update and is not a substitute for Tesla’s own release notes. For the specifics of what changed in FSD 14.3.9, see the sourced release notes and reporting linked above.
Photo by Saksham Vikram.
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