Teslas appear to once again be struggling with the “phantom braking” phenomenon, in which cars on Autopilot apply the brakes when it detects an obstruction that doesn’t exist, according to Electrek and National Highway Traffic Safety Administration (NHTSA) complaints.
These instances pose serious safety issues because other drivers are not expecting the cars in front of them to slam on the brakes, increasing the odds of rear-end collisions. They also undermine the general narrative that Autopilot and similar automatic-braking systems make driving safer, because they introduce a new hazard of sudden, inexplicable brake-slamming that didn’t previously exist with human drivers.
Automakers have had problems with phantom braking for years, but Teslas seem to be especially prone to them, as extensively documented in various driver forums such as the popular TeslaMotors subreddit. Because Tesla owners tend to be more technically savvy and observant to software variations, numerous theories have always been floated whenever the phantom braking gets particularly bad for any given driver. But because NHTSA, the regulatory agency tasked with overseeing road safety, has so far failed to take advanced driver assist features like Autopilot seriously as a potential safety issue, it is little more than a guessing game as to how well these systems work and why they might be buggy.
Which is exactly where we find ourselves with the most recent problems reported by Electrek. The website said “things have been seemingly getting worse lately for many Tesla owners” in the last few weeks in particular. This is seemingly a separate and distinct issue from the recent Full Self-Driving Beta recall for aggressive phantom braking among other issues because it impacts Teslas without FSD Beta, running plain old Autopilot. The issues with Autopilot appear to be linked to the recent 2021.40 software update, but are only affecting some vehicles running that software. Electrek concludes that “There’s undeniably a significant uptick in phantom braking events, but it doesn’t seem to be affecting all cars the same way.”
For now, Tesla gets an outsized amount of attention on the phantom braking issue both because of its cavalier attitude towards using public roads as software testing grounds and because it updates its software the most frequently. But as most every other automaker moves towards frequent over-the-air updates to roll out new features as a new revenue stream, it is possible these problems will become more common.
The phantom braking issue highlights a problem with automatic safety features in cars that is often ignored or even dismissed by its proponents: Software quality ebbs and flows over time. It is not enough to simply make one good version once, because every future version has the potential to break what previously worked. For example, Musk said phantom braking would be “fixed” in October 2020; maybe it was, maybe it wasn’t, but either way it is obviously back. This concept is not strange to computing. Almost every app update features “bug fixes and performance improvements.” That’s fine when talking about the latest update to Google Docs, less so when it has the potential to cause a pileup on the interstate.