Ratings and test results on every car CR purchases and tests:
Brake lights are a major safety feature on vehicles that provide a fair warning to drivers traveling behind them. On this bonus episode we discuss recent findings in Consumer Reports' tests that discover potential safety issues with brake lights on EVs from Genesis, Hyundai, Kia, and Mercedes-Benz.
SHOW NOTES
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00:00 – Introduction
00:22 – Topic: Braking without brake lights
01:02 – Disclaimer
01:55 – What is one-pedal driving
03:57 – Hyundai; Kia; Genesis: issue with one-pedal driving
05:21 – CR’s test findings
07:46 – Federal law for vehicle brake lights
09:09 – CR’s recommendation for one-pedal operation in Hyundai; Kia; Genesis EVs
11:36 – Mercedes-Benz: one-pedal driving issue
14:21 – CR’s recommendation for one-pedal driving in Mercedes-Benz EVs
15:12 – Conclusion
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Brake Lights Can Fail to Provide Fair Warning on Some Electric Vehicles
Hybrids/EVs
Is an Electric Car Right for Your Next Road Trip
Hot, New Electric Cars That Are Coming Soon
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Not just EVs, though the problem is biggest with them. All cars should have brake lights illuminate when deceleration reaches a specific rate. Manual transmission cars have always been able to downshift and rapidly decelerate without using brakes or illuminating brake lights.
Very true – this reminds me of when a new law was passed to require EVs to make noise at low speeds. The legislation should have required all vehicles to emit a minimum amount of noise at low speeds. Many modern ICE cars make very little noise at low speeds, and now they make less noise than EVs.
So, you’re saying it hasn’t been an issue since the dawn of the automobile but it is now?
@Tim yup, strange how it only becomes a problem with EVs doing it and not other vehicles using “engine braking”…isn’t that conveeeenient
Shoutout to @TechnologyConnections for doing a great video on this topic as well!
Really great research and focus on the consumer!
Shout out to Alec Watson at the Technology Connections YouTube channel who was the first to bring this issue to my attention. And thank you CR for shining your light on this issue. I think it’s critical that automakers and regulators pay attention to this and take action ASAP.
Yes, thank *you* for shouting out Technology Connections, which CR *did not* do in this video.
Indeed, it’s good that Alec made the video, raised awareness and has gotten the necessary attention with it to have the issue addressed. And let’s hope that manufacturers have learned their lesson as according to the written CR article, this isn’t the first time, but the i3 also has had this issue in the past.
I’m an Ioniq 6 owner myself, in Europe though, and fortunately, my car has the expected behavior, but I was concerned for the first few days after that video.
Very strange that the article came out a few weeks after the video and this over a month later and they don’t acknowledge it. The CR article seems too coincidental to not have been influenced by it. https://www.youtube.com/watch?v=U0YW7x9U5TQ
@Loncey Mills What is your proof that CR was informed that was the source of the question?
Also, if Alec noticed it, how did you arrive at certainty that CR didn’t also, in the course of evaluating vehicles also arrive at this conclusion?
The Simpsons did it first. Sorry, I meant to say The Technology Connections did it first, as usual.
Very interesting video! I was somewhat surprised by CR’s discovery of this issue because my Tesla has always illuminated its brake lights when slowing down under regenerative braking, so I assumed that other EVs would as well. It had not occurred to me that there was no rule requiring it. But also as you pointed out, I was well aware that gas or Diesel vehicles with manual transmissions also can decelerate quite quickly and do not actuate their brake lights unless the brake pedal is pressed. I used to drive Diesel cars, and their high compression engines would slow a car very nicely without or before using the service brakes. I can’t say that I ever thought about the brake light issue with manual transmission cars, or ever heard anyone mention concerns about that. I wonder if large Diesel trucks, in particular, actuate their brake lights when they use their “jake brakes,” which also slow the vehicles quite quickly, but I do not know if that type of equipment can be actuated without also using the service brakes. (Might be worth asking that question….) Oh,, and here is another related question — Do vehicles with the “hill hold” feature actuate their brake lights? I have that on my car, so I will be curious to check.
cr did not discover this
Stopped cars with brake lights on are rear ended all the time, CR only has an issue when it is EVs why because their paying ownership Ford foundation wants to slow down EV adoption as they cannot make EVs at a profit.
Why were manual transmission autos not a subject of CRs reports for the last 100 years? Are cars parked on the side of the road without lights not an issue? As a driver it is up to you to see these potential issues, yet when Tesla is trying to automate these issues CR makes defeat devices and manipulates how to crawl in the backseat when everyone with a brain knew that car had been driven manually by drunks.
Wow! A friend’s Kia EV6 was rear ended at a traffic light. I wonder if it was a factor. When I was a young knucklehead, I used to try to stop by downshifting my VW Bug for fun. Thanks CR for shining a break light on this.
I’ve come close to rear ending at least a couple teslas (my parents as well) because they decelerate a lot without turning on their brake lights. I don’t know if CR found anything with Teslas not putting their brake lights on, but I’ve certainly delt with situations where a tesla in front of me is slowing down at a quite significant rate, without their brake lights turning on.
Also I’m glad AEB can detect slowing cars whether their brake lights are on or off. It has warned me a couple times about a Tesla slowing down in front of me, without brake lights on.
Pretty glad I didn’t end up buying an Ioniq 5 last year with this issue and the ICCU – loss of power/mobility issue happening. What a shitshow.
Where did you keep your right foot while downshifting?
@Nick B Tesla lights in general are too small/dim. I was on I-66 a couple months ago during a bad thunderstorm. There was a Tesla in the line of traffic and it took real focus to not lose it because they kept changing lanes, essentially asking to be hit. They had their lights on, but they were so small/dim it disappeared between wiper swipes. Not good with a dark grey vehicle that is essentially the same color as a wet road.
Long before EVs, I thought it would be so helpful if cars had “status” lights in the back….green light for when the car is accelerating or maintaining constant speed/using cruise control. A yellow light would indicate coasting/slowing. And red lights would indicate traditional braking.
You beat me to it, I also thought before EV’s that it would be nice to have a yellow light when taking you foot off the gas pedal to show you’re slowing and maybe about to apply the brakes. Also thought of blinking brake lights instead of yellow but that may be misunderstand as someone using the hazard lights.
Never thought of having a green light, but that’s not a bad idea either. Smart thinking (I think).
@Sam connecticut I’d also like to see traffic lights offer the same courtesy, to tell you how much time is left on the green. That way, we give drivers more information and clear the dilemma zone. Paint a lateral yellow line on the road, and if you are before that yellow line, then slow down for a yellow. If you are after that yellow line, speed up for a yellow.
I was disappointed that the article on CR’s website did not show what the other EVs did, only highlighted the Hyundai/Kia/Genesis and Mercedes EVs. And some PHEVs also have aggressive One-Pedal modes which will bring them to a stop, these should be tested as well.
Keep up the good work!
They said all the other EVs they tested performed as expected.
As much as they can, they do _not_ want to enunciate “Tesla” unless it’s in a negative light.
Interesting, my Subaru Forester, has brake light indicators in the cabin… so that I know when the brake lights are on, and when they aren’t. I recommend this for all cars. 🙂
Preferably via fiberoptics visible in the rear-view mirror like old Cadillacs from the ’70s-90s, to give an indication of the actual function of each brake light.
Thanks for your insight. My Kia Niro PHEV has one pedal driving and Adaptive Cruise Control. The cruise control will bring my car to a complete stop when the car ahead of me stops. I have no idea if my brake lights come on during the deceleration or the stop, or if a certain deceleration value triggers the light. Have you tested this on any of your cars? Thanks again for publicizing a very important safety issue.
My Forester has adaptive cruise. The car illustration in the IP shows the tail lights and they turn on with the brake lights the same as the door logo illuminates when a door is opened.
As per CR: The European Union has a regulation that requires EVs to illuminate their brake lights anytime the regenerative-braking system’s deceleration rate exceeds 1.3 meters per second squared, or about 0.13 g. Sounds like a standard that should be implemented in the US.
I own a Tesla Model 3. I understand that the brake lights illuminate at .11 G’s of deceleration. You can also see if your brake lights are on by looking at the avatar of the car on the screen.
Excellent info. I follow EV news and channels but had not heard about the brake light issue.
Thank you for probably the most important CR segment addressing existing public safety issues at large. The only way you can make it even more informative is to list all manufacturers’ models having the same problem – not just 2!
I was mortified to see in the rear view mirror a car nearly rear ending me when test driving Nissan Ariya earlier this year!
The salesman next to me in front passenger seat, demonstrated the different regeneration braking levels using paddle shifter on the steering wheel with my foot off accelerator pedal while “coasting” at 40 MPH. Deceleration G force at level B was equal to moderately strong breaking and no brake light went on! This was at nighttime so when using brake pedal passenger cabin would get a red glow, that couldn’t be missed. I asked him if he realized it and he said: “the driver behind needs to pay attention”.
What could he say? That the car he was hoping to sell me was fundamentally unsafe for the public on the road?
This is really a disturbing situation and I applaud CR for investigating and establishing communication with the auto companies and regulatory authorities for a solution. On a related topic, some vehicles have an “auto hold” feature that allows the driver to lift off the brake pedal when the car is stopped at a traffic signal or in traffic. When that occurs, do the brake lamps remain illuminated even though the brake pedal is not being pressed? If not, it would seem that the same potentially dangerous situation would exist as drivers approaching from the rear might not realize that the car ahead is actually stopped.
This is a very interesting video. And hopefully as time goes on we chose the best stoplamp modification with EVs.
Great investigative reporting! This is a major safety concern, to the point I would never consider a MB or Hyundai EV until it’s fixed.
Thanks CR. It’s been a while since I’ve driven a tractor trailer but they had the ability to use a separate trailer brake that brakes the trailer and not the tractor. It can significantly reduce the vehicle’s speed but no brake lights come on and is used to straighten out a potential jackknife situation. Your standard of applying the brake lights upon 1G of deceleration would be helpful if applied to this situation as well. Can you follow up with this?
I was driving behind the new regular chevy bolt and noticed it was slowing down without any brake lights coming on. I immediately knew it was due to regen braking but the average driver would not. I totally agree this is an urgent issue that needs to get remedied quickly by automakers.
What’s crazy, is how many customers that Hyundai group and Mercedes are going to lose with this problem becoming commonly known as a safety issue.