A Tesla Semi prototype was spotted in transport, presumably, after having completed several weeks of winter testing near its cold-weather testing facility outside of Delta Junction, Alaska.
Various sightings of the Tesla Semi from over the weekend suggest that the all-electric semi-truck was making its way down the western seaboard of the United States from Washington, through Oregon, and back to its Fremont, California test facility.
Video captures of a Tesla Semi being transported on the back of a semi-trailer shows the prototype’s salt-covered exterior as it makes its way back from cold-climate performance testing under snowy conditions.
Tesla Semi have done some #SosialDistancing @elonmusk hardcore testing? pic.twitter.com/keqweQ6GSh
— John D. (@Real_John_D) March 23, 2020
In January, Tesla noted in an email communication to Semi-truck reservation holders that the truck was undergoing hazard testing at its test facility in Fremont, California.
“Over the last few months, we have continued testing the trucks in real world conditions. We also spent time at a proving ground to evaluate the truck’s resilience over rougher road conditions. Using instruments mounted on the vehicle, we collected road input data to ensure the trucks can handle severely degraded roads. At our own Fremont test facility, we subjected the trucks to a number of high energy, discreet events such as curb strikes, pot holes, and other harsh inputs to confirm the truck is capable of handling common hazards.”
In the same communication, the company indicated that Tesla Semi has already completed “important engineering development checkpoints” and would be rolling out more “production-representative vehicles” vehicles in 2021.
Ahead of planned production, Tesla Semi would undergo several weeks of winter testing. The company has an extreme cold testing facility in Alaska where its vehicles, including the Tesla Model S and Model 3, undergo intense winter testing.
“In the short term, the team is gearing up for several weeks of winter testing to validate the truck’s performance in cold weather and low traction conditions. We are excited to share insights from the winter with you, as we will be able to highlight the major advantages of electric traction and motor control, which no diesel powertrain can match,” said the company in an email to a Tesla Semi reservation holder.
Actually I re-read the letter it says they will have limited volume production 2nd qtr of 2020. pic.twitter.com/A2hTYyTVdz
— chris (@chris31402370) January 9, 2020
Tesla has not confirmed where Semi-truck production will take place, only noting in its fourth-quarter earnings update letter that the facility would be in North America.
CEO Elon Musk indicated in the Q4 earnings call that Tesla Semi would be initially produced in limited quantity as the company focused efforts on increasing battery production capacity. Given the size of the all-electric truck and its energy needs, having a strong supply of battery cells is crucial to preventing a strain on supply for its consumer vehicles like the Model 3 and Model Y.
“So, the thing we’re going to be really focused on is increasing battery production capacity because that’s very fundamental because if you don’t improve battery production capacity, then you end up just shifting unit volume from one product to another and you haven’t actually produced more electric vehicles,” said Musk when asked about the Tesla Semi. “So, that’s part of the reason why we have not, for example, really accelerated production of the Tesla Semi because it does use a lot of cells and unless we’ve got a lot of battery cells available, then — and say like accelerating production of the Tesla Semi would then necessarily mean making pure Model 3 or Model Y cars. And so, we’ve got a really — make sure we get a very steep ramp in battery production and continue to improve the cost per kilowatt-hour of the batteries.”
A Tesla Semi was captured on Sunday, making its way down Interstate 5 in Olympia Washington, roughly 60 miles south of Seattle. Credit: Tvlog.
A Tesla Semi caught fire in Hayward, California, which caused both directions of traffic to shut down for hours before being completely reopened early on Wednesday, the California Highway Patrol said.
The fire occurred just after 5:30 local time in Hayward on Tuesday, as the Semi caught fire in the southbound lanes of I-880 before CHP officials made the decision to shut down both lanes of traffic due to potential risks from hazardous chemical smoke.
There were no injuries reported.
🚨 A Tesla Semi reportedly caught fire, with California Highway Patrol confirming. The Semi was on I-880 SB
An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year
— TESLARATI (@Teslarati) October 28, 2026
The cause of the fire is currently unknown, as neither Tesla nor the CHP have not determined a cause.
However, some images taken before the Semi was completely destroyed by the fire seem to indicate this might have been an older unit, as it appears to be one of the designs that Tesla shipped as part of its pilot program, before revising it and starting mass production just a month ago.
@Tslachan From on of the videos looks like it’s an old Semi (not the refresh version that recently started production) https://t.co/KzwmR2kXow
— Area Under The Curve 🎗️ (@AreaUnderCurve) October 28, 2026
At the time of publication, CHP had not returned our request for a comment for additional details, including the Semi involved and any potential collaboration on an investigation between the CHP and Tesla. We will update this story when we hear back from them.
The southbound lanes were reopened at 3:30 a.m. on Wednesday, with the northbound lanes opening last night a few hours after the fire began. The CHP did state that the lithium batteries were “incredibly difficult to extinguish,” according to NBC Bay Area.
The truck’s driver said that the Semi caught fire, but he did not have an explanation.
An estimated 5,000 to 7,000 semi-truck and large commercial vehicle fires occur on U.S. roadways every year.
Tesla’s launch of the “Emergency Drive Away” function a few months back offered owners a safe option to evacuate an area if they were in reasonable danger. The function finally got its first use in the real world, but it appears it was by mistake.
A video shared by u/Joshalander in the r/TeslaLounge subreddit recorded the instance from his vehicle and said the incident took place in Austin this past weekend during the city’s F1 Race.
“Was charging around 6 AM this past Sunday in Austin before heading to the F1 race and heard a pop. Looked over and saw the new emergency drive-away feature in action. Genuinely felt bad for the dude when he got out and realized what happened, since he looked exhausted and only seemed to half-read the prompts.”
🚨 Here’s the first look at Tesla’s Emergency Drive Away function in action:
Apparently this driver accidentally enabled it and drove forward; you can see the Supercharger pull with the car.
Tesla said previously this would cost up to $25k if not used properly. https://t.co/B4qQRrsO6B
— TESLARATI (@Teslarati) October 28, 2026
Emergency Drive Away unlatches the Supercharger connector from the vehicle, but still causes damage to both the car and the Supercharger. Tesla has said that it will cost up to $25,000 in repairs to have everything fixed back to normal.
Additionally, the company said that if it were not used in an emergency situation, the driver of the vehicle who activated the Emergency Drive Away feature would be responsible for all repair costs.
Tesla constitutes the following situations as reasonable justifications for activating the feature:
- You face an immediate threat to your life or personal safety.
- You must leave the area immediately.
- Exiting the vehicle is unsafe.
- Unplugging the charge connector would unreasonably delay your departure or expose you to a risk to your personal safety.
After using the feature, Tesla requires the driver to schedule Service so the car can be inspected.
News
Tesla’s Cybercab battery design could make robotaxis even cheaper
Tesla built the Cybercab’s battery pack with spare room for a future switch to LFP.
Tesla built the Cybercab’s battery pack with empty space inside it on purpose, and the reason points to a cheaper robotaxi down the road.
Robert Sumpf, Tesla’s director of mechanical design engineering for battery modules and packs, said the extra room beside and beneath the Cybercab’s modules was left there so the company can move to lithium iron phosphate cells later. “So, we protected this pack to go to an even lower energy dense chemistry as we scale and need to bring LFP into the platform,” Sumpf said in a Cybercab deep dive with Munro Live.
The Cybercab runs on Tesla’s own 4680 cells with a nickel chemistry today. LFP cells store less energy for their size, so a straight swap would cut range. The reserved space lets Tesla add more LFP cells to make up the difference. In return, Tesla would get cells that cost less, run cooler and survive more charge cycles. LFP became the most used EV battery chemistry in the world last year.
Not all of that room was planned for a chemistry change. Lars Moravy, Tesla’s Vice President of Vehicle Engineering, said part of it exists because “we didn’t need as many batteries as we thought we did.” Tesla told Sandy Munro in early 2025 that it was targeting a Cybercab pack under 50 kWh with close to 300 miles of range.
The pack also breaks from the structural design Tesla used in some Model Y and Cybertruck builds. Instead of potting hundreds of cells into one block, the Cybercab uses four separate, individually sealed modules, so a bad module can be replaced without scrapping the whole pack. Sumpf was blunt about the older approach, giving the Model Y structural battery “a grade D” because it was hard to build and nearly impossible to repair. He estimated a fully structural pack gains about 10% more cell volume, but said “the issue is the service cost.”
That cost matters more for a car that rarely sits parked. Cybercab chief engineer Eric Earley said replacing an entire pack “before half a million miles is a killer on cost,” which is why remanufacturing and serviceability were built into the design from the start.
The same Munro Live tour produced Moravy’s admission that the Cybercab line at Giga Texas is now outpacing Robotaxi deployments, along with a look at the robotaxi’s unorthodox paint process. Tesla is aiming to deliver the first Cybercabs to outside customers by the end of 2026, though Elon Musk has said the vast majority will stay owned by Tesla and run as a transport service.
Sumpf did not give a date for an LFP version, name a cell supplier or say how a chemistry change would affect range. For now, the 4680 cars keep piling up: Texas DMV records from Tuesday list 544 Cybercabs authorized for Tesla’s Robotaxi fleet, more than the 507 Model Ys on the same roster for the first time.
Tesla Semi catches fire in California: what we know
Tesla’s ‘Emergency Drive Away’ function gets its first use in the real world
