Credit: Federal Court Documents

One-pedal driving is not causing Tesla electric vehicles to suddenly accelerate when parked, according to federal regulators. For almost as long as Tesla has been selling cars, it has been hit with sporadic accusations of parked cars accelerating when they shouldn’t. Known to the industry as “sudden unintended acceleration,” the question for regulators is whether the problem is a human one or an engineering one, and over the years, engineers who think they’ve found the culprit have petitioned the National Highway Traffic Safety Administration to force a recall. These efforts usually fail, as was the case today, when NHTSA said it would not tell Tesla to recall every EV it built since 2013.

Because electric motors are also generators, EVs use regenerative braking to recover energy when they slow down rather than wasting that kinetic energy as heat (and maybe a bit of sound) via the friction brakes. In many battery EVs and just about any hybrid I can think of, a brake-by-wire system blends the two together—the driver uses the left pedal as normal, and the car slows down. Some automakers (I’m looking at you, Porsche) think this is the only way a driver should slow their EV. But an electric motor can also be programmed to regeneratively brake when the driver lifts their foot from the throttle, and in Tesla’s EVs (as well as Rivian’s and Lucid’s), this is the only way to regen, as there is no brake-by-wire system, only traditional hydraulic friction brakes.

Technically, I just described lift-off regen, but if the car has been programmed to come to a complete stop when you take your foot from the accelerator, that’s one-pedal driving. Some EV drivers absolutely love one-pedal driving; others don’t. I like one-pedal for low-speed driving or when I want something similar to engine braking. But according to the petition sent to NHTSA in 2023 by a Greek engineer, this causes a “short-circuit” in Tesla drivers’ brains.

The last petition regarding Teslas and sudden unintended acceleration involved claims regarding a voltage spike in the car’s inverter. Not so here—Costas Lakafossis presented NHTSA with a lengthy white paper that tries to prove that human error isn’t the problem but that there are instead “very specific patterns that repeat themselves in almost every one of these SUA accidents, all pointing to the same cause of possible confusion and the same lack of appropriate pre-emptive measures in the programming of the Human-System Interface of modern self-driving cars.”

Essentially, because a driver doesn’t need to hold down the brake pedal when starting a Tesla, its driver might put a foot on the accelerator by mistake, Lakafossis claimed, thus explaining about 200 incidents in which Teslas have crashed into garage walls or other parked cars. But as Lakfafossis noted in his petition, NHTSA has already determined that all of those crashes were driver error, and that’s the case today as well. One-pedal driving is common across the industry, NHTSA said, and adding the equivalent of a brake transmission interlock to 2.3 million Teslas will not happen.

FSD probe deepens

Humans can’t see in this glare, and neither can camera-based vision systems.
Credit: Getty Images

Thursday was a less good day for Tesla’s relationship with NHTSA. Yesterday, NHTSA expanded a “preliminary analysis” into an “engineering analysis”—i.e., a more thorough investigation—into Tesla’s vision-only “FSD” system. Without a second sensor modality to rely on—virtually all other automakers use radar and sometimes lidar, too—Tesla wrote software to detect if the camera feeds were too degraded to rely upon. Should this be the case, the driver would be notified to take control. That’s the idea, at least.

NHTSA said it’s worried that the system “fails to detect and/or warn the driver appropriately under degraded visibility conditions such as glare and airborne obscurants.” After reviewing nine crashes, the agency said “the system did not detect common roadway conditions that impaired camera visibility and/or provide alerts when camera performance had deteriorated until immediately before the crash occurred.” NHTSA also said the number of linked crashes may be underreported, and it is adding six more incidents to the analysis.

If NHTSA finds an engineering defect, Tesla could be forced to recall more than 3.2 million vehicles.