The on screen animation of your car's environment will change. The computer vision generated road that the car is driving on, denoted by two lines, will change into a rainbow which is similar to that of Rainbow Road, the final level in each version of the video game Mario Kart.
At the same time, the song (Don't Fear) The Reaper by Blue Oyster Cult plays in the cabin of the vehicle. Notably, the version of the song that plays is taken from the Saturday Night Live skit, More Cowbell, in which music producer "The Bruce Dickinson", played by host Christopher Walken, encourages Gene Frenkle, played by then cast member Will Ferrell, to play his instrument, the cowbell, with zeal.
As part of the easter egg, Christopher Walken can be heard stating his lines from the skit, that he "has a fever" and that the "only prescription, is more cowbell". While the music and lines from the skit will stop after a minute or two, the rainbow road will continue indefinitely until autosteer is disengaged.
If the car is not using autosteer, and the "Easter Egg Drawer" is used to activate the effect, tapping the cowbell will result in a message entitled "Rainbow Road". The message includes instructions on how to activate rainbow road, that Autosteer must be engaged, and a description of the effect. This information is followed by the exclamation, "I gotta have more cowbell!"
This easter egg works on the Models S, 3, X, and Y. Autosteer capable vehicles only.
To activate this easter egg: With autosteer engaged, push the right stalk behind the steering wheel down four times in rapid succession. The same control stalk is used to switch from park to drive or reverse, and to activate autopilot.
Subscribe
Subscribe to our newsletter to stay up to date on the latest Tesla news, upcoming features and software updates.
FSD’s insatiable appetite for AI compute is taking shape once again at Giga Texas, where Tesla is building out Cortex 2.0 — its second large-scale GPU supercomputer cluster — on the facility’s north side.
This confirmation comes thanks to the detailed research and findings by Giga Texas drone pilot Joe Tegtmeyer, who shared his findings on X.
For months, there has been some speculation on what this new site would be - new storage, the Optimus production line, preparation for the Cybercab’s unboxed assembly process, and more. Now, thanks to permits filed by Tesla, we know that this new area is destined to become the second supercomputer destined for FSD training.
Cortex 2.0
There are some key details we can unpack from what we’ve learned about Cortex 2.0. The new facility will be on the north side of Giga Texas, opposite Cortex 1.0, which is on the south side. The permits explicitly tie the usage of this expansion to Cortex 2.0, namely through the fact that it is a data center.
This is actually a change from Tesla’s original plans - the northern section was intended to be used as a central campus support facility, with three smaller facilities and water storage tanks. Now, it has been redesignated as Cortex 2.0 and is one large structure.
The permits that have been filed have already been approved and cover the foundations, underground water mains, and building itself. The steel structure is actively being put together on the concrete foundations, and about 50% of the roof decking is already complete, bringing the exterior shell closer to completion.
Fueling FSD’s Brain
The deployment of Cortex 2.0 is the latest in Tesla’s massive and ongoing investment in the computational power required to train FSD. While this primarily covers FSD for cars, this will also eventually apply to Optimus, which is powered by the same AI4 computer and also runs a variant of FSD.
This isn’t Tesla’s first foray into large-scale AI infrastructure and won’t be their last. Alongside Dojo, their home-grown AI supercomputer, Tesla has been partnering closely with Nvidia to ensure they have the GPUs necessary to do all the hard work. Cortex 2.0 is the next iteration, and once it's fully online, we can expect that Tesla’s work on FSD will accelerate even further.
Especially since Elon is planning something truly outrageous once again:
Been thinking about the fastest way to bring a terawatt of compute online.
That is roughly equivalent to all electrical power produced in America today.
With European Tesla owners eagerly awaiting any news on FSD in Europe, we’ve seen Tesla tease FSD, and also point out exactly what the barrier has been - regulatory approval. Now, following the latest meeting of UNECE, new regulatory amendments are set to unlock “System-Initiated Maneuvers” (SIM) on highways across participating European nations.
This development, highlighted by Kees Roelandschap on X, notes that the latest documents from the United Nations Economic Commission for Europe (UNECE) center on amendments to UNECE regulation 171. These changes were formally adopted into UNECE during the WP29 World Forum in March 2025.
Now, the amendment that will enable SIM will come into force on September 26, 2025. This six-month period after approval is standard UNECE procedure and allows objections from party states that would halt the implementation. Objections to UNECE amendments are genuinely rare, with 95% of amendments passing without objection once the World Forum adopts them.
What This Means for FSD in Europe
System-initiated maneuvers will allow your Tesla to perform actions autonomously, such as changing lanes on a highway, while the driver remains fully responsible for supervision. This is a substantial step up from current regulatory standards that only allow for suggested maneuvers or require explicit driver initiation for every automated maneuver.
This inches towards the more normal “hands-off, eyes-on” approach that Tesla has taken with FSD Supervised in North America and China. This regulatory change will help to provide the legal frameworks needed to deploy more advanced autonomy capabilities in Europe, at least matching what’s available on highways in North America.
The UNECE regulation will apply to all countries that adopt its standards, including the European Union, Japan, and South Korea - unless they specifically block it. This is a relatively positive development, but there are some hiccups.
This regulation only allows for system-initiated maneuvers on highways, not low-speed roadways. That means the city streets portion of FSD’s capabilities - including handling ‘Start FSD from Park` and reaching your destination’s parking spot - still won’t be available in Europe.
In addition, the UNECE framework has stricter requirements for driver monitoring and attentiveness - which means that some nags, including the dreaded wheel nag, are likely to remain a key portion of the experience.
Progress on autonomous driving regulations in Europe has been fraught with indecision and caution, which has been a source of frustration for many who are watching the everyday progress of FSD in North America, and more recently, in China. Even with individual countries recently approving testing of FSD on public roads, harmonized UNECE regulations are the key to wider, consistent deployment, which will allow everyday customers to use it as well.
While the path to full parity with North America may be long and involve even more regulatory machinations, the upcoming implementation of System-Initiated Maneuvers is a big step forward for Tesla owners in Europe. It is a key piece of the puzzle that will help Tesla bring some more features of FSD to Europe, assuming the September timeline holds.