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Stanford studies human impact when self-driving car returns control to driver
Researchers involved with the Stanford University Dynamic Design Lab have completed a study that examines how human drivers respond when an autonomous driving system returns control of a car to them. The Lab’s mission, according to its website, is to “study the design and control of motion, especially as it relates to cars and vehicle safety. Our research blends analytical approaches to vehicle dynamics and control together with experiments in a variety of test vehicles and a healthy appreciation for the talents and demands of human drivers.” The results of the study were published on December 6 in the first edition of the journal Science Robotics.
Holly Russell, lead author of study and former graduate student at the Dynamic Design Lab says, “Many people have been doing research on paying attention and situation awareness. That’s very important. But, in addition, there is this physical change and we need to acknowledge that people’s performance might not be at its peak if they haven’t actively been participating in the driving.”
The report emphasizes that the DDL’s autonomous driving program is its own proprietary system and is not intended to mimic any particular autonomous driving system currently available from any automobile manufacturer, such as Tesla’s Autopilot.
The study found that the period of time known as “the handoff” — when the computer returns control of a car to a human driver — can be an especially risky period, especially if the speed of the vehicle has changed since the last time the person had direct control of the car. The amount of steering input required to accurately control a vehicle varies according to speed. Greater input is needed at slower speeds while less movement of the wheel is required at higher speeds.
People learn over time how to steer accurately at all speeds based on experience. But when some time elapses during which the driver is not directly involved in steering the car, the researchers found that drivers require a brief period of adjustment before they can accurately steer the car again. The greater the speed change while the computer is in control, the more erratic the human drivers were in their steering inputs upon resuming control.
“Even knowing about the change, being able to make a plan and do some explicit motor planning for how to compensate, you still saw a very different steering behavior and compromised performance,” said Lene Harbott, co-author of the research and a research associate in the Revs Program at Stanford.
Handoff From Computer to Human
The testing was done on a closed course. The participants drove for 15 seconds on a course that included a straightaway and a lane change. Then they took their hands off the wheel and the car took over, bringing them back to the start. After familiarizing themselves with the course four times, the researchers altered the steering ratio of the cars at the beginning of the next lap. The changes were designed to mimic the different steering inputs required at different speeds. The drivers then went around the course 10 more times.
Even though they were notified of the changes to the steering ratio, the drivers’ steering maneuvers differed significantly from their paths previous to the modifications during those ten laps. At the end, the steering ratios were returned to the original settings and the drivers drove 6 more laps around the course. Again the researchers found the drivers needed a period of adjustment to accurately steer the cars.
The DDL experiment is very similar to a classic neuroscience experiment that assesses motor adaptation. In one version, participants use a hand control to move a cursor on a screen to specific points. The way the cursor moves in response to their control is adjusted during the experiment and they, in turn, change their movements to make the cursor go where they want it to go.
Just as in the driving test, people who take part in the experiment have to adjust to changes in how the controller moves the cursor. They also must adjust a second time if the original response relationship is restored. People can performed this experiment themselves by adjusting the speed of the cursor on their personal computers.
“Even though there are really substantial differences between these classic experiments and the car trials, you can see this basic phenomena of adaptation and then after-effect of adaptation,” says IIana Nisky, another co-author of the study and a senior lecturer at Ben-Gurion University in Israel “What we learn in the laboratory studies of adaptation in neuroscience actually extends to real life.”
In neuroscience this is explained as a difference between explicit and implicit learning, Nisky explains. Even when a person is aware of a change, their implicit motor control is unaware of what that change means and can only figure out how to react through experience.
Federal and state regulators are currently working on guidelines that will apply to Level 5 autonomous cars. What the Stanford research shows is that until full autonomy becomes a reality, the “hand off” moment will represent a period of special risk, not because of any failing on the part of computers but rather because of limitations inherent in the brains of human drivers.
The best way to protect ourselves from that period of risk is to eliminate the “hand off” period entirely by ceding total control of driving to computers as soon as possible.
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Tesla revamped Semi spotted, insane 1.2 MW charging video releases
These developments highlight Tesla’s ongoing refinements to the vehicle’s design and infrastructure.
Tesla is gearing up for high-volume Semi production in 2026, with the Class 8 all-electric truck’s revamped variant being spotted in the wild recently. Official footage from Tesla also showed the Semi achieving an impressive 1.2 MW charging rate on a charger.
These developments highlight Tesla’s ongoing refinements to the vehicle’s design and infrastructure.
Revamped Tesla Semi sighting
Tesla Semi advocate @HinrichsZane, who has been chronicling the progress of the vehicle’s Nevada factory, recently captured exclusive drone footage of the refreshed Class 8 truck at a Megacharger stall near Giga Nevada. The white unit features a full-width front light bar similar to the Model Y and the Cybercab, shorter side windows, a cleared fairing area likely for an additional camera, and diamond plate traction strips on the steps.
Overall, the revamped Semi looks ready for production and release. The sighting marks one of the first real-life views of the Class 8 all-electric truck’s updated design, with most improvements, such as potential 4680 cells and enhanced internals, being hidden from view.
1.2 MW charging speed and a new connector
The official Tesla Semi account on X also shared an official video of Tesla engineers hitting 1.2 MW sustained charging on a Megacharger, demonstrating the vehicle’s capability for extremely rapid charging. Tesla Semi program lead Dan Priestley confirmed in a later post on X that the test occurred at a dedicated site, noting that chargers at the Semi factory in Nevada are also 1.2 MW capable.
The short video featured a revamped design for the Semi’s charging port, which seems more sleek and akin to the NACS port found in Tesla’s other vehicles. It also showed the Tesla engineers cheering as the vehicle achieved 1.2 MW during its charging session. Dan Priestley explained the Semi’s updated charging plug in a post on X.
“The connector on the prior Semi was an early version (v2.4) of MCS. Not ‘proprietary’ as anyone could have used it. We couldn’t wait for final design to have >1MW capability, so we ran with what had been developed thus far. New Semi has latest MCS that is set to be standard,” the executive wrote in a post on X.
Check out the Tesla Semi’s sighting at the Nevada factory in the video below.
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Tesla FSD successfully completes full coast-to-coast drive with zero interventions
Tesla community members celebrated the milestone on X, and the feat earned praise from some of the electric vehicle maker’s executives.
A Tesla owner has successfully completed a full coast-to-coast drive across the United States on Full Self-Driving (FSD) Supervised. The trip was accomplished with zero interventions.
Tesla community members celebrated the milestone on X, and the feat earned praise from some of the electric vehicle maker’s executives.
FSD Coast-to-Coast
The coast-to-coast feat was accomplished by Tesla owner Davis Moss, who drives a stealth gray Model 3 with AI4 hardware. Based on data from the FSD database and a community tracker, the last 10,638.8 miles Moss drove in his Model 3 were completed using FSD 100% of the time. His vehicle is equipped with FSD v14.2.1.25, which was installed 12 days ago.
As per Moss in a celebratory post on X, his Model 3 was able to complete a full coast-to-coast drive across the United States in 2 days and 20 hours. His trip started at the Tesla Diner in Los Angeles, CA, and it ended in Myrtle Beach, SC. Overall, his trip spanned 2,732.4 miles.
“This was accomplished with Tesla FSD V14.2 with absolutely 0 disengagements of any kind even for all parking including at Tesla Superchargers,” Moss stated in his post. He also added in later comments that there were zero close calls during the trip.
Tesla community celebrates
The FSD milestone trip was widely lauded by members of the Tesla community, especially since a coast-to-coast drive with zero interventions has been cited by Elon Musk as a target since October 2016, when Autopilot 2.0 was unveiled. At the time, Musk initially estimated that a coast-to-coast drive across the United States should be possible by the end of 2017. Considering Moss’ feat in his Model 3, it appears that Elon Musk’s estimate was not impossible at all. It was just late.
Musk himself celebrated the milestone on X, and so did Tesla VP of AI Software Ashok Elluswamy, who wrote “World’s first fully autonomous coast-to-coast drive, done with Tesla self-driving v14. Congrats and thank you @DavidMoss!” in a post on X. The official Tesla North America account also celebrated the feat, writing “First Tesla to drive itself from coast to coast w/ FSD Supervised. 0 interventions, all FSD” on X.
Elon Musk
Elon Musk: Tesla Model Y is world’s best-selling car for 3rd year in a row
The Model Y has now established an impressive streak that would otherwise have been impossible before Tesla.
Elon Musk has announced that the Tesla Model Y has become the world’s best-selling car by volume for the third consecutive year, capping 2025 with another dominant performance.
The Model Y has now established an impressive streak that would otherwise have been impossible before Tesla.
Three years in a row
Musk posted on X: “Tesla Model Y is now officially the world’s best-selling car for the third year in a row!” The CEO’s comment echoed an update that Tesla included in its 2025 recap, which highlighted, among other things, the Model Y’s incredible streak.
The Model Y has held the title since 2023, outperforming traditional leaders like the Toyota RAV4 and Corolla thanks to its bang-for-the-buck nature and its stellar combination of practicality, performance, and tech. The Model Y is also lauded as one of the safest vehicles on the road, making it an ideal choice for families in key markets such as China.
An impressive 2025
The Model Y’s sales feat in 2025 is especially impressive considering the introduction of the vehicle’s new variant. Tesla’s changeover to the new Model Y across its global factories resulted in sales being paused for some time in the first quarter. As per Tesla’s Q1 2025 vehicle delivery and production report, “the changeover of Model Y lines across all four of our factories led to the loss of several weeks of production in Q1.”
This suggests that the Model Y’s sales remained strong in 2025 to the point where it could still claim the title of the world’s best-selling vehicle by volume, even with its sales being throttled during the first quarter of the year. It would then be interesting to see just how far the Model Y can go in 2026, especially considering the rollout of new variants like the six-seat extended wheelbase Model Y L, the affordable Model Y Standard, and the top-tier Model Y Performance.