Collision mitigation slammed on my brakes when it should not have

Discussion in 'Clarity' started by ukemike, Oct 1, 2019.

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  1. ukemike

    ukemike New Member

    It scared the snot out of me. I was on a 1 way road and the car in front of me was turning left. There is no way I was going to hit him though I might have been closer than is polite, and in fact by the time it hit the brakes I was past him. But it slammed on the brakes anyway. Thank god I didn't get rear-ended. Is there a way to turn this feature off permanently? I hate it. I don't want some buggy-*** computer or defective sensor deciding to slam on the brakes at random, it's totally unacceptable.
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  3. KClark

    KClark Active Member

    ukemike, I can understand your anger and your need to vent about something that isn't acceptable. A few months ago I wrote about my experience with ACC slamming on the brakes and the car in back of me almost hitting me when no one was directly in front of me on a freeway but someone in the lane to my right was exiting. But if you're expecting any kind of sympathy or understanding be forewarned. I got lectures about not following too close, lectures about not driving correctly, lectures about not understanding my Clarity, lectures about how I must have been mistaken and it probably never happened like I had explained, etc, etc. In other words, a lot of hot air that had nothing to do with what I experienced or what I wrote or what actually happened, because of course random guys on the internet know more about what you experienced than the person who was there when it happened.

    One thing that was actually helpful, when I had my first service I told the dealer that my Honda sensing seemed to be hyper finicky about things that happened to the right of center instead of what happened directly in front of me. They checked the sensors and adjusted them and things improved. I had turned off the lane departure function because it was alarming a dozen times and more on my 22 mile commute. After the adjustment I was able to turn it back on and I haven't had any problems with it or with ACC or collision mitigation since then. I would have the dealer check it out.
    Domenick likes this.
  4. Aaron

    Aaron Member

    I had the same thing happen to me at a protected green arrow. The car in front of me was making a u-turn and my Clarity slammed on it's brakes. The vehicle behind me also slammed on his brakes and honked at me. Scary.......
  5. neal adkins

    neal adkins Active Member

    There is a button right beside the charge door opener to turn off collision mitigation.There's also vehicle stablity assist and road departure mitigation buttons.
    Last edited: Oct 1, 2019
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  6. cokeb5

    cokeb5 Member

    I also had this happen to me once on a road trip. I was cresting over a hill and the lane slightly shifted to the left at the top, there was no car in my lane or the lane to my right and it just slammed on the brakes hard. I had to smash the gas pedal instinctively to avoid being rear-ended. I'm still not sure what the radar detected, possibly the hill I was cresting over?
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  8. jdonalds

    jdonalds Well-Known Member

    My wife has complained that the car, numerous times, slammed on the brakes. Again it was just lucky that no car was following too close behind or there would have been an accident. There must be driving habits that differ between my wife and I as this has never happened to me.

    We did turn off the collision mitigation which solved the problem. Honda needs to rethink their software for this feature. It is supposed to be a safety feature but it is doing just the opposite.
  9. Dan Albrich

    Dan Albrich Active Member

    So no slamming here (but since I don't have this issue personally, I don't have exact page references in the manual). Here are some thoughts:
    - Collision mitigation *can* be turned off, although if memory serves it automatically re-enables each time you drive. So you may have to press the button each time before heading out.
    - I know for sure there's a system setting likely under vehicle that sets how sensitive this stuff is. I don't know what the default is. i.e. if it's most sensitive, in the middle, or least. But have a look in the menu. This setting *is* tuneable.
  10. KentuckyKen

    KentuckyKen Well-Known Member

    Mine has never slammed on the brakes in a little over a year and a half. It has on several occasions flashed and beeped at me, but only when I got too close to a car turning in front of me. (You know how you tend to get closer than usual to a car that’s half out of your lane as they turn.)
    So I think it’s possible to have the CMBS work like it’s supposed to with very few false braking or even false warning events. Nothing is perfect in life, but mine is acceptably close.

    I would have the dealer check the alignment of the radar unit. It’s underneath the plastic cover that is between the radiators and the front grill. When I had the cover off to install an air horn (no more wimpy Roadrunner “meep-meep” for me), I noticed that it is adjustable.
    E10 likes this.
  11. jdonalds

    jdonalds Well-Known Member

    I checked it this evening. The Collision Mitigation defaults to "On" when the car starts. To turn it off hold the button for a few seconds.
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  13. MrFixit

    MrFixit Well-Known Member

    This is very a complicated problem, and the car manufacturers have tried to address it with a relatively 'simple' system.
    The number of situations that can occur on the road are virtually infinite.

    There is always a balancing act between sensitivity and false alarms. If there are never any false alarms, then the system will also fail to trigger sometimes when it is really needed.

    I don't know how Honda compares to other vehicle mechanizations, but I believe these systems are mandated at this point and they will not be going away. I'm sure they will improve over time with additional technology, etc...

    I am certain that these CMBS systems [Collision Mitigation Braking System] have prevented accidents. They is little doubt that they have caused some too. It would be very interesting if some independent agency were to attempt to monitor the efficacy of these systems across manufacturers and report on the statistics of accidents prevented vs. accidents caused. This would apply pressure on the manufacturers to improve these systems at a faster pace and identify ones that are particularly problematic.
  14. craze1cars

    craze1cars Well-Known Member

    Back in 2016, darn near every auto maker that sells cars in the US has committed to making auto braking and collision mitigation systems standard by model year 2022. We are not quite there yet but almost, and many have already implemented it across the board.

    The logistics and expense of trying to decipher what has occurred between automated and natural forces and human interactions in nearly every collision after it occurs is simply impossible No agency could take that on and come up with accurate or truly meaningful results, so it won’t happen. Way too many variables. We just need to learn to drive with the systems.

    I’ve had a few very short hard braking events occur both my 2016 Civic which has the same system, and the Clarity. Usually when I know darn well I’m gonna swerve around a left turning car in front of me, and a few times with sharp curves and oncoming traffic or whatever temporarily confused the system. Every time it has been a quick hard brake pump and near instant release by the system. It has surprised me, but never bothered me much...probably slows the car down by 5 mph at best and then figured out “oops...never mind.” I think kinda nice to know the system is working. And such events are rare. Maybe 6 times in 100k miles I have driven the 2 cars? And if the brake check by the system surprises a tailgater I don’t feel too sorry for them.

    Still waiting for someone to say the system CAUSED an accident. Several say “almost.” Based on this I’m gonna go out on a limb and say these systems have prevented or lessened the impact of accidents far more frequently than they have actually caused them.

    Those who don’t like the system or don’t trust it can just push a simple button to shut it off. I’ll leave mine on and I Hope most do. I feel the good outweighs the bad 100 fold. Yes there are subtle glitches. Every new car going forward will gradually get smarter. Remember when airbags first came out and were blamed for injuries, breaking arms or whatever? They got smarter and now have variable deployment forces and better never hear about those issues much anymore...just a bit of rug burn on the face which is a whole lot better than a face full of glass or steering wheel. Same will happen here. Systems will improve with time.
    Last edited: Oct 2, 2019
  15. cokeb5

    cokeb5 Member

    Sounds like your experiences with it have been pretty lucky then. I've owned my car for less than a month now, and had it happen twice in about ~1,500 miles. The second time it did slow down around 5 mph as well, and then corrected so it wasn't a huge deal. The first time it braked incredibly hard, locking all passenger's seatbelts from the braking force and slowed down around 15+ mph. I believe it would have continued slowing down as well but I quickly floored the accelerator which stopped the braking. There wasn't a car in front of me for either instance. It definitely appears that experiences are very different depending on the car, which makes me think calibration issues may be at play.
  16. leehinde

    leehinde Active Member

    A slight elevation on the freeway has triggered unneeded braking for me.
  17. Sandroad

    Sandroad Well-Known Member

    This response from the car has come up a number of times before in other threads. Since the action is so unnerving for those of us it’s happened to, I suspect it will continue to be a source of threads and posts. The programming for the Clarity CMBS (maybe all Honda’s?) is very different than that of both Toyota’s I’m familiar with. I would characterize the Clarity CMBS response as: “OMG, we’re all gonna die!” and the Toyota CMBS response as: “Relax, I got this.” I just really wish no car would slam on the brakes unexpectedly. I feel like we are all a beta tester for self-driving cars.
  18. craze1cars

    craze1cars Well-Known Member

    In hindsight I think my airbag analogy missed the mark. Better IMO after more thought is to liken this issue to the early years of ABS. Any of us who have been driving a while likely will remember our first experiences with archaic ABS systems in the late 80s when they first started coming out in most new cars. Every driver on earth was taught until then to pump the brakes if skidding. Suddenly rules change and now it’s cram your foot down and hold it there no matter what. Compounding the learning curve was these phantom ABS applications that would occur at the subtle slide of going over 2 pebbles on dry pavement. This would give the sensation of a decelerating car suddenly releasing its brakes as you’re approaching a stop sign or object...not to mention the entire brake pedal would start shaking like crazy and loud groaning and chattering from under the hood/dash, and I’ll be first to admit it was all kinda scary! And this would scare some people into pulling their foot off the pedal at a moment they shouldn’t! And I had several close calls that would NOT have occurred if my ABS systems would not have activated. But no actual wrecks. Due to all of this Most experienced drivers HATED early ABS systems and some were pulling fuses to disable them and everything else: Those systems had slow processors and mapping and sensors and whatever, and they just did funny things sometimes. But with every year they got better. Then they got integrated into stability control. And today in a new car it is darn near impossible to sense that the car is doing ANYTHING to save your bacon on ice and snow except for a flashing light on the dash. Pedal barely vibrates if at all, you don’t hear the systems working, and the car simply holds its line in a controlled manner.

    And now here we find ourselves in the earlier stages of collision mitigation systems. And we’ll have the same growing pains. They’re not perfect but as drivers we need to learn to work with it. If you feel it’s defective complain and take it in. If you simply hate it, you can shut it off with the button. I see no other options. I personally love it and will require it on every car I own going forward and will never deactivate it. I still insist the accidents it prevents vs the accidents it causes as a whole over the industry is likely 99 to 1. As a fallible human I’ll take those odds and trust the system to save my butt someday if I flake out for whatever reason, even if it glitches periodically. I frankly have total faith that if I fully pass out behind the wheel due to a medical thing or whatever, these new cars will keep me in my lane and eventually bring me to a reasonably safe stop before it slams into anything or anyone or drives me off the side of a bridge. That would be nice for my car to do in my mental absence, God forbid I ever need it. But someone will need it...

    These systems are the first stepping stones toward widespread self driving cars. Things will improve.
    Last edited: Oct 2, 2019
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  19. ukemike

    ukemike New Member

    Wow it's been a while since any post I have made anywhere got such a response. Thanks everyone. I think I will schedule a dealer visit for an adjustment, and when I remember I have been pushing the button to turn off the random brake actuation system.

    BTW I have my sensitivity set to "long" because I appreciate the warnings. There have been one or two times when a car several seconds ahead of me got hard on their brakes hard at just the moment I was looking over my shoulder in hopes of changing lanes. I would have seen them in time anyway, but the warning got my attention right away and I was able to slow calmly and gently. I love that warning. I'm all about warnings, they are great. Information is power. I'm not very happy at all about the car taking my control away from me. This technology is not ready for prime time. I am quite convinced that I am still a lot better driver than my Clarity is.

    I've also had the quick brake bump some of you described, when I was going around a right curve and there was oncoming traffic, there was 0 possibility of a collision, but I guess the sensor saw the car "in front" of me and jabbed the brakes. I also once had it bump the brakes briefly when I was rolling down a left turn only lane at maybe 15mph and there was stopped traffic on my right. There was a big box truck that I guess the sensor "saw". In neither case was I on a collision course and in neither case did the braking start until I was passing the "target". Both of those bothered me and made me concerned but the one I mentioned in the OP was sustained, engaged the anti-lock, and brought us nearly to a stop. I smashed the accelerator pedal down in hopes of getting going before someone behind me hit me. My son was pretty freaked out and actually cursed me, "what the hell are you doing Dad?!?!!" He got his learner permit and now he's the supreme critic of all my driving foibles.

    I was hoping to avoid getting any car with all these safety nanny features. I don't believe they are mature yet, but the incentives on this Clarity made it such a great deal, and I wanted an ev or something close. I'm not fond of the lane keeping assist. At first it would just ping-pong down the lane, back and forth inside the lane like a drunk. I changed the settings and it got better, but I see no advantage to it. It doesn't allow you to let it drive, I find it reacts to turns much later than I would, starting the turn when we've drifted to the outside of the lane way more than I would allow, and that makes me nervous. Same with the adaptive cruise control, it reacts much later and much more abruptly than I would unless I were being totally negligent, and when I set it to say 65 and let off the pedal, it slows to 62 before speeding back up. Every morning at about the same place traffic slows from 65 down to 20 or 30. When I've had ACC on it waits and waits and doesn't slow, I loose my nerve and get on the brakes myself. I think the Clarity only "sees" about 150 feet which is totally insufficient for safe highway driving. So all of these features seem to make more work, increase driving my stress, do their thing worse than I do on my own, and one of them I suspect might be trying to kill me. :)

    I love this car, except for the drunken safety nanny (DSN) system.

    This increases my desire to get a dash cam. It's not just other drivers, but my car itself I may need to prove caused an accident.
    Domenick likes this.
  20. ukemike

    ukemike New Member

    CMBS = Car Might Brake Suddenly :D
  21. KClark

    KClark Active Member

    I am convinced of the same, but oddly enough, accepting this, along with getting the sensors adjusted, has let me make peace with the safety suite. When I first started using it I felt like I was a passenger in a car with a timid and scared driver at the wheel and it drove me nuts. I always naively assumed that these new safety features would drive as well as I do, and when they didn't it got me upset and sometimes angry. After the sensor adjustment I also adjusted my attitude, and now I have the same wary opinion of the safety features that I do of other drivers, I expect them both to do stupid things occasionally and I try to be prepared for when they do. (Although I'll admit that your experience is hard to be prepared for.)

    I pretty much agree with your opinion of LKAS. I've tried it both commuting and on a long interstate trip and it didn't seem to add any value. I never use it. I do use ACC everyday, it does have its quirks, but after 8 months of daily driving with it I can usually predict when they will appear and I'm always ready to disengage or hit the accelerator when they do. Like you, I also find its behavior when engaging, that it always slows down by almost 5mph below the set point before slowly coming back to speed, a little infuriating since I've driven cars with CC for 20 years and none of them had a problem staying at speed when initially engaged. I have found one strategy that seems to avoid it. If I want to set ACC for 65 I'll speed up to about 68 and then take my foot off the accelerator, when the speed drifts down to 65 I engage ACC and it seems to stay at that speed instead of doing the slow down/speed up.

    But also like you, in spite of these things I really like my Clarity. It is a perfect commuting car for Southern CA with our high gas prices.
    Last edited: Oct 2, 2019
  22. Folks, read the manual. Please.

    The LKAS is not intended for you to let the car drive itself.

    It is designed to alert you that you are about to depart your lane. It is deactivated when you use the turn signals to indicate your intentions.
  23. KClark

    KClark Active Member

    Landshark, I think you're the one that needs to read the manual. LKAS stand for Lane Keeping Assist System which the Honda website says, "Adjusts steering to help keep you centered in a detected lane." It is not designed to alert you that you are about to depart your lane, that would be the RDM or Road Departure Mitigation System.

    I never said that I thought LKAS was a self driving system, where did you get that from? I said that it doesn't add any value to my driving experience and I don't use it. Your mileage may vary and that's great.
    Sandroad likes this.

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