NHTSA is investigating whether EVs should be retrofitted with pedestrian warning systems
Teslarati
The National Highway Transportation Safety Administration (NHTSA) is investigating whether hybrid-electric and electric vehicles from 1997 to present should have external speakers installed for pedestrian safety. The investigation was officially opened on January 27th, according to Teslarati.
In 2018, Federal Motor Vehicle Safety Standard (FMVSS) 141 passed. This new safety standard required electric vehicles and hybrid-electric vehicles with a weight of 10,000 pounds (4,536 kilograms) or less to have a pedestrian warning system (PWS). A PWS is an external speaker on the vehicle that plays a sound when the vehicle is traveling at low speeds. This ensures pedestrians can hear vehicles if they’re nearby.
Sounds of the PWS While Driving
EVs and hybrid-electric vehicles can be extremely quiet, especially at low speeds. EVs can go unheard when approaching stop signs, crosswalks, and intersections, especially if there are other environmental sounds as well.
In July 2022, a petition was received by the NHTSA that urged the organization to require all EVs and hybrid-electric vehicles to have external noisemakers installed on them. Any vehicles without them, regardless of their manufacture date, would be considered to have a safety defect, according to the NHTSA’s Office of Defect Investigation.
“The petitioner asserts that hybrid and electric vehicles to which the standard does not apply should be found to contain a safety defect. In support of the petition, the petitioner includes findings contained in a bill introduced in the House of Representatives in 2009, the Pedestrian Safety Enhancement Act of 2009, H.R. 734, 111th CONG. (2009).”
The passing of the Pedestrian Safety Enhancement Act of 2009, which was signed into law by President Barack Obama in 2011, says all vehicles should have a feature for “alerting blind and other pedestrians of the presence and operation of nearby motor vehicles to enable such pedestrians to travel safely and independently in urban, rural, and residential environments.”
Should the NHTSA agree and side with the petitioners, roughly 9.1 million cars across multiple manufacturers would be affected. These include Polestar, Tesla, Toyota, Nissan, BMW, Honda, and more.
Tesla’s Pedestrian Warning System
Tesla started installing their PWS in their vehicles in 2019. This was a mandatory change for Tesla, as both the US and EU passed laws requiring electric vehicles to make some kind of noise due to their quiet sound levels at slower speeds. The noise is played continuously until speeds of 19mph are reached, per the US regulation.
“The Pedestrian Warning System (PWS) is an audible tone played when the vehicle is moving slowly (up to 19 mph) in either Drive or Reverse,” Tesla said at the time in a memo to staff. “The sound is played via a speaker mounted in the front fascia and alerts nearby pedestrians of the car’s presence in low-speed situations.”
Tesla started manufacturing vehicles for this long before the regulations went into effect. Tesla enthusiast and YouTuber DÆrik noticed the speaker grill on the front underside of his 2018 Performance Model 3.
PWS Also Adds Boombox Feature
In classic Tesla and Elon Musk fashion, they went the extra mile and added some playful goodies for owners to get a laugh out of. They called this new feature “Boombox,” which allowed sounds to be played using the vehicle’s external speaker. For example, while in park or drive, the vehicle was able to fart, play music, and any noises the user uploaded.
Unfortunately, the NHTSA thought this was distracting and banned the feature while in drive. It's currently available in most regions around the world while the vehicle is parked.
If NHTSA requires Tesla to retroactively install PWS in their vehicles built before 2019, owners will at least have the Boombox feature to look forward to. During Tesla's 2022 holiday update, Tesla also added the ability to use Emissions Testing Mode through the Tesla app. If your vehicle is equipped with the PWS, then the vehicle will play the farting sound through its external speaker. Otherwise, it will be played through the internal speakers - which isn't quite as much fun
Tesla’s Cybertruck has officially earned a 5-Star Safety Rating from the NHTSA—an impressive achievement given the vehicle’s design. The achievement demonstrates Tesla’s engineering prowess. As one engineer points out, it wasn’t an easy feat.
Interestingly, the NHTSA only recently disclosed the results, despite the crash tests being completed a while ago. According to Lars Moravy, Tesla’s VP of Vehicle Engineering, the team had been aware of the 5-star rating for quite some time. While the reason for the delay remains unclear, now that the results are public, Tesla’s engineers can finally share how they achieved the rating.
Crumple Zones
Wes Morril, the Cybertruck’s Lead Engineer, wrote about the crash test video on X recently, addressing the claims that the Cybertruck doesn’t have a crumple zone. He also posted a side-by-side video (below) of the engineering analysis and the crash test itself.
Engineered Crash Safety
There’s a lot of engineering precision at play when a Cybertruck is involved in a crash. Unlike traditional crash structures that rely on crash cans and collapse points, the Cybertruck’s front gigacasting is designed to absorb and redirect impact forces in a highly controlled manner.
It all starts with the bumper beam, which crushes within the first few milliseconds of a high-speed impact. At the same time, the vehicle’s sensors rapidly analyze the crash dynamics and determine the optimal deployment of safety restraints, including airbags and seat belt pre-tensioners. These split-second actions are crucial in keeping occupants safe.
As the crash progresses, the vehicle’s structure deforms in a carefully engineered sequence. The drive unit cradle bends, directing the solid drive unit downward and out of the way, allowing the gigacasting to begin absorbing impact forces.
The casting crushes cell by cell, methodically dissipating energy in a controlled manner. This gradual deceleration reduces the g-forces transferred to occupants, making the crash much less severe. As the gigacast begins crushing, the safety restraints are deployed.
As Wes points out in his post - you can see how accurate the virtual analysis and modeling were. The video shows the simulated crash side by side with the real-life crash test and they’re almost identical. All that virtual testing helps provide feedback into the loop to design a better and safer system - one that is uniquely different than any other vehicle on the road.
All the armchair experts claimed the Cybertruck has no crumple zone and I get it, the proportions seem impossible. It was a tough one and there is a lot of engineering that went into it. Let me break it down for you:
Tesla has pioneered the use of single-piece castings for the front and rear sections of their vehicles, thanks to its innovative Gigapress process. Many automakers are now following suit, as this approach allows the crash structure to be integrated directly into the casting.
This makes the castings not only safer but also easier to manufacture in a single step, reducing costs and improving repairability. For example, replacing the entire rear frame of a Cybertruck is estimated to cost under $10,000 USD, with most of the expense coming from labor, according to estimates shared on X after high-speed rear collisions.
These insights come from Sandy Munro’s interview (posted below) with Lars Moravy, Tesla’s VP of Vehicle Engineering, highlighting how these advancements contribute to the improvements in Tesla’s latest vehicles, including the New Model Y.
However, with the new Model Y, Tesla has decided to go a different route and eliminated the front gigacast.
No Front Casting
Tesla’s factories aren’t equipped to produce both front and rear castings for the Model Y. Only Giga Texas and Giga Berlin used structural battery packs, but these were quickly phased out due to the underwhelming performance of the first-generation 4680 battery.
Tesla has gone back to building a common body across the globe, increasing part interchangeability and reducing supply chain complexity across the four factories that produce the Model Y. They’ve instead improved and reduced the number of unique parts up front to help simplify assembly and repair.
There is still potential for Tesla to switch back to using a front and rear casting - especially with their innovative unboxed assembly method. However, that will also require Tesla to begin using a structural battery pack again, which could potentially happen in the future with new battery technology.
Rear Casting Improvements
The rear casting has been completely redesigned, shedding 7 kg (15.4 lbs) and cutting machining time in half. Originally weighing around 67 kg (147 lbs), the new casting is now approximately 60 kg (132 lbs).
This 15% weight reduction improves both vehicle dynamics and range while also increasing the rear structure’s stiffness, reducing body flex during maneuvers.
Tesla leveraged its in-house fluid dynamics software to optimize the design, resulting in castings that resemble organic structures in some areas and flowing river patterns in others. Additionally, manufacturing efficiency has dramatically improved—the casting process, which originally took 180 seconds per part, has been reduced to just 75 seconds, a nearly 60% time reduction per unit.
Advancements in die-casting machines and cooling systems have allowed @Tesla to dramatically reduce cycle times and improve dimensional stability. pic.twitter.com/WB5ji67rvV
Tesla’s new casting method incorporates conformal cooling, which cools the die directly within the gigapress. Tesla has been refining the die-casting machines and collaborating with manufacturers to improve the gigapress process.
In 2023, Tesla patented a thermal control unit for the casting process. This system uses real-time temperature analysis and precise mixing of metal streams to optimize casting quality. SETI Park, which covers Tesla’s manufacturing patents on X, offers a great series for those interested in learning more.
The new system allows Tesla to control the flow of cooling liquid, precisely directing water to different parts of the die, cooling them at varying rates. This enables faster material flow and quicker cooling, improving both dimensional stability and the speed of removing the part from the press for the next stage.
With these new process improvements, Tesla now rolls out a new Model Y at Giga Berlin, Giga Texas, and Fremont every 43 seconds—an astounding achievement in auto manufacturing. Meanwhile, Giga Shanghai operates two Model Y lines, delivering a completed vehicle every 35 seconds.
![A Look at the Tesla Cybertruck’s Crumple Zones [VIDEO]](https://www.notateslaapp.com/img/containers/article_images/cybertruck/cybertruck-crash-test.webp/e43ef2433bd6e44ae8db63421604a4fb/cybertruck-crash-test.jpg)
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