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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.
Elon Musk
Elon Musk calls out $2 trillion SpaceX IPO valuation as ‘BS’
In a swift rebuke on X, Elon Musk dismissed reports claiming SpaceX had confidentially filed for an initial public offering targeting a valuation above $2 trillion, labeling the information as unreliable.
Elon Musk is quick to call out any false information regarding him or his companies on his social media platform, known as X.
A recent report that claimed SpaceX was aiming to go public with an IPO in the coming weeks at a massive valuation of $2 trillion was called out by Musk, who referred to it as “BS.”
In a swift rebuke on X, Elon Musk dismissed reports claiming SpaceX had confidentially filed for an initial public offering targeting a valuation above $2 trillion, labeling the information as unreliable.
The exchange highlights ongoing media speculation about the rocket company’s future and Musk’s frustration with what he views as inaccurate financial reporting. The report came from Bloomberg.
Don’t believe everything you read.
Bloomberg publishes bs.
— Elon Musk (@elonmusk) April 3, 2026
The controversy erupted on April 2, 2026, when influencer Mario Nawfal amplified claims from Bloomberg.
The outlet posted that SpaceX had boosted its IPO target valuation above $2 trillion, describing it as potentially one of the largest public offerings in history. Musk challenged the story.
It echoes past instances where Musk has corrected valuation rumors about his companies, emphasizing that speculation often outpaces reality.
Background context adds nuance.
Earlier reports indicated SpaceX had filed confidential IPO paperwork with the U.S. Securities and Exchange Commission, potentially positioning it for a record-breaking debut that could eclipse Saudi Aramco’s 2019 listing.
Initial estimates pegged a possible valuation north of $1.75 trillion, building on a post-merger figure around $1.25 trillion after SpaceX absorbed xAI. A subsequent Bloomberg update claimed advisers were floating figures above $2 trillion to investors, with the offering potentially raising up to $75 billion.
SpaceX remains a private powerhouse. Its achievements include thousands of Starlink satellites providing global broadband, routine Falcon 9 rocket reusability, and a mission to slash launch costs, along with ambitions for Starship to enable Mars colonization.
The company also benefits from government contracts with NASA and the Department of Defense. A public listing could democratize access for retail investors while subjecting SpaceX to greater scrutiny and quarterly reporting pressures.
Critics of the reports point to the confidential nature of filings, which limits verifiable details. Musk has previously downplayed inflated valuations, once calling an $800 billion figure for SpaceX “too high.”
Supporters argue that hype around mega-IPOs, especially amid the ongoing AI fervor, fuels premature narratives that distract from core technical milestones, such as full Starship reusability and Starlink constellation expansion.
The incident reflects broader tensions in tech finance. Anonymous sourcing in valuation stories can drive market chatter and betting activity, yet it risks misinformation.
Bloomberg defended its reporting through multiple articles citing “people familiar with the matter,” but Musk’s blunt dismissal resonated widely on X, with users piling on to question media reliability.
Whether SpaceX ultimately goes public remains uncertain. Musk has teased an IPO tied to Starlink maturity, but priorities center on engineering breakthroughs over Wall Street timelines. For now, the $2 trillion figure joins a list of rumored milestones that Musk insists should be taken with skepticism.
Elon Musk
Elon Musk reveals date of SpaceX Starship v3’s maiden voyage
The announcement arrives after Flight 11 on October 13 of last year, which concluded a busy 2025 testing campaign. Since then, SpaceX has focused on ground testing, including cryoproofing of Ship 39 and preparations for Booster 19, the first V3 Super Heavy.
SpaceX CEO Elon Musk has revealed the timeline for the next Starship launch. It will be the first launch using SpaceX’s revamped design for Starship, as its v3 rocket will take its maiden voyage sooner than many might expect.
Musk announced on April 3 on X that the next Starship flight test, and the first flight of the upgraded v3 ship and booster, is 4 to 6 weeks away. The update signals the end of a nearly six-month hiatus since the program’s last launch.
Elon says the first V3 Starship launch will occur in 4-6 weeks
It will be the first Starship launch since Flight 11 on October 13, 2025 https://t.co/QnnYPTdbUu
— TESLARATI (@Teslarati) April 3, 2026
The upcoming mission, designated as Starship’s 12 integrated flight test (IFT-12), marks a significant milestone. It will be the debut of the v3 configuration, featuring a taller Super Heavy Booster and Starship upper stage. The changes SpaceX has made with the v3 rocket and booster are an increased propellant capacity and the more powerful Raptor 3 engines.
Earlier predictions from Musk in March had pointed to an April timeframe, but the latest timeline now targets a launch window in early to mid-May 2026.
The V3 iteration represents a substantial evolution from previous Starship prototypes. Engineers have optimized the design for improved manufacturability, higher thrust, and greater efficiency. Raptor 3 engines deliver significantly more power while reducing weight and production costs compared to earlier variants.
With these enhancements, SpaceX aims to boost payload capacity toward 200 metric tons to low Earth orbit in a fully reusable configuration — a dramatic leap from the roughly 35-ton target of prior versions. Such capabilities are critical for ambitious goals, including NASA’s Artemis lunar missions and eventual crewed flights to Mars.
The announcement arrives after Flight 11 on October 13 of last year, which concluded a busy 2025 testing campaign. Since then, SpaceX has focused on ground testing, including cryoproofing of Ship 39 and preparations for Booster 19, the first V3 Super Heavy.
Recent activities have involved static fires, activation of the new Pad 2 at Starbase in Boca Chica, Texas, and integration of Raptor 3 engines.
A prior incident with an early V3 booster on the test stand in late 2025 contributed to the delay, necessitating additional assembly and qualification work.
Musk’s timeline updates have become a hallmark of the Starship program, often described with characteristic optimism.
SpaceX’s Starship V3 is almost ready and it will change space travel forever
While past targets have occasionally shifted by weeks, the rapid iteration pace remains impressive. However, don’t be surprised if this timeline shifts again, as Musk has been overly optimistic in the past with not only launches, but products under his other companies, too.
SpaceX continues to refine launch infrastructure, including new propellant loading systems and tower mechanisms designed to support higher cadence operations. A successful V3 flight could pave the way for more frequent tests, tower catches of both booster and ship, and progression toward operational reusability.
The v3 debut is viewed as a transition point for Starship, moving beyond experimental flights toward a system capable of supporting large-scale deployment of Starlink satellites, lunar landers, and interplanetary transport.
Success on IFT-12 would demonstrate not only the new hardware’s performance but also SpaceX’s ability to recover from setbacks and maintain momentum.
As the 4-to-6-week countdown begins, anticipation builds at Starbase. Teams are finalizing vehicle stacking, conducting final pre-flight checks, and preparing for regulatory approvals. The world will be watching to see if Starship V3 can deliver on its promise of transforming humanity’s access to space.
Elon Musk
SpaceX to launch military missile tracking satellites through new Space Force contract
SpaceX wins a $178.5M Space Force contract to launch missile tracking satellites starting in 2027.
The U.S. Space Force awarded SpaceX a $178.5 million task order on April 1, 2026 to launch missile tracking satellites for the Space Development Agency. The contract, designated SDA-4, covers two Falcon 9 launches beginning in Q3 2027, one from Cape Canaveral Space Force Station in Florida and one from Vandenberg Space Force Base in California. The satellites, built by Sierra Space, are designed to bolster the nation’s ability to detect and track missile threats from orbit.
The award falls under the National Security Space Launch Phase 3 Lane 1 program, which Space Force uses to move payloads to orbit on faster timelines and at more competitive prices. “Our Lane 1 contract affords us the flexibility to deliver satellites for our customers, like SDA, more easily and faster than ever before to all the orbits our satellites need to reach,” said Col. Matt Flahive, SSC’s system program director for Launch Acquisition, in the official press release.
SpaceX is quietly becoming the U.S. Military’s only reliable rocket
The SDA-4 contract is the latest in a long string of national security wins for SpaceX. As Teslarati reported last month, the Space Force recently shifted a GPS III satellite launch from ULA’s Vulcan rocket to SpaceX’s Falcon 9 after a significant Vulcan booster anomaly grounded ULA’s military missions indefinitely. That move made it four consecutive GPS III satellites transferred to SpaceX after contracts were originally awarded to its competitor.
This didn’t come without a fight and dates back years. SpaceX originally had to sue the Air Force in 2014 for the right to compete for national security launches, at a time when United Launch Alliance held a near monopoly on the market. Since then, the company has steadily displaced ULA as the dominant provider, and last year the Space Force confirmed SpaceX would handle approximately 60 percent of all Phase 3 launches through 2032, worth close to $6 billion.
With missile defense satellites now part of its launch manifest alongside GPS, communications, and reconnaissance payloads, SpaceX is giving hungry investors something to chew on before its imminent IPO.
Elon Musk calls out $2 trillion SpaceX IPO valuation as ‘BS’
Elon Musk reveals date of SpaceX Starship v3’s maiden voyage
