Thread by @maxrdlb

#teslafiles #autopilot - Chapter 6: Massive Pile-Up in the Tunnel

"Frequent phantom braking on two-lane highways. Makes autopilot almost useless."

How big is the risk for Tesla drivers? The search for an answer to this question leads to a converted cow barn in the Bavarian district of Landsberg am Lech.

This is where Jürgen Zimmermann has his workshop. Up to 700 Teslas roll onto his lift each year, he says. Zimmermann films as he inspects the cars, removes wheels and curses axle shafts. Hundreds of thousands watch his clips on Youtube.

The automotive technician is a fan of Tesla. He calls the feeling of driving such a car "insane". Despite all his admiration for the brand, Zimmermann is not blind to its quirks. He has a theory for the problems with the unwanted accelerations.

Tesla has long used a front radar with lower resolution. For the system, there was "a car in front of me - yes or no," nothing in between, says Zimmermann. If the car drove around a tight curve, the radar no longer saw the car in front and accelerated.

In May 2021, Tesla removed the radar sensor. The task of traffic monitoring is now only carried out by the cameras built into the car.

An artificial intelligence evaluates their videos in real time, compares the data with maps and data from other Tesla vehicles, and gives the system driving instructions. Zimmermann says that the problem with the accelerations should therefore become smaller with every new car.

The data from the Tesla files also suggest this. Since the company has been relying on cameras, it apparently happens less often that the cars accelerate on their own.

But while the complaints about unwanted acceleration decreased in the data package, a new phenomenon appeared: phantom braking.

On the morning of November 24, 2022, Elon Musk announced on Twitter, "Tesla Full Self-Driving Beta is now available to everyone in North America who requests it from the car's screen." Four hours later, there was a massive pile-up in a tunnel in San Francisco.

A surveillance camera shows a white Tesla Model 3 changing to the passing lane and then abruptly braking. Seven other cars pile up. Nine people are injured. According to the Tesla driver, he had activated the autopilot. The NHTSA is now also investigating this case.

Automotive technician Zimmermann believed that abrupt stops could be related to a faulty calibration of the cameras. However, a self-experiment with weights in the trunk did not confirm his theory.

Zimmermann now suspects that the phantom braking is mainly a software problem. The autopilot would therefore confuse shadows or other harmless things with obstacles.

Indeed, Tesla lets its customers train the artificial intelligence for such cases. According to a presentation from Investor Day in March 2023, the company has alone fed the system with 14,000 videos "from its own fleet" showing "braking due to a parked car."

In other words, there have already been more than 14,000 phantom brakes alone due to stationary vehicles. And Tesla knew about it.