Dynamic Radar Cruise Control on 2022 Prius: Problem

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Rapher, Jul 1, 2022.

  1. Rapher

    Rapher New Member

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    I recently bought a 2022 Prius XLE. It's a wonderful car except for what I believe is one fatal flaw. I shared this with my local dealer, who shared my concern. Apparently, this is a 'new feature'. When one sets the dynamic radar cruise control, the vehicle 'generally’ corrects the car speed with a car/truck in front that is moving slow, i.e., by slowing down. If one decides to pass on the left and activates the left turn signal the Prius automatically begins to accelerate EVEN IF I DON'T SWITCH LANES. It eventually corrects itself, but only after several seconds. Coupling this acceleration with the car/truck ahead possibly slowing down, can lead to a fatal accident. According to the dealer tech, this turn signal override can not be turned off. This situation does not occur when moving to the right lane. That is, activating the right turn signal does not automatically make the car accelerate until the car has cleared into the right lane. To add to this complication, let's say you wish to pass on left and there is a car in the left lane, the turn signal override still activates and you accelerate. Now you are boxed in and MUST deactivate the cruise control. I know of no other car that has this 'feature'. That is, cars do not accelerate until they have cleared into the new lane of traffic. This should be corrected by Toyota or at least create an option enabling the driver to turn off this feature. When one passes on the left the typical procedure is to turn on the signal, look to make sure the lane is available, and then proceed to pass. Toyota's new 'feature' makes this dangerous. Thoughts? If others have experienced this issue-please formally notify Toyota. If there are enough complaints, and hopefully no accidents, maybe Toyota will modify its software.
     
  2. bisco

    bisco cookie crumbler

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    and nhtsa as well
     
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  3. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I'm in a rented 2022 Camry this week and it does the same thing.

    And I love it!

    I'll admit it surprised me the first time, but I thought it was graceful and intuitive.

    Satan will be in treatment for frostbite before I try to pass on the right. It's an unnecessary safety risk and I'm completely OK with this feature being incompatible with bad driving habits.
     
  4. AzWxGuy

    AzWxGuy Weather Guy

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    For comparison, if perhaps the 2022 version is different from my 2021, my DRCC with full-speed range will accelerate upon signaling into the left lane. but if I will be following a vehicle already in the left lane it will immediately slow down to maintain the preset following distance. I'm not sure but I think the acceleration only begins when I execute the lane change. I'll check it next week if I can (and remember). The following distance is active all the time and enforced regardless of lane changes, which I have found out in a panic stop sort of way when someone ahead of me suddenly slows to make a right turn. I also really like using this system. It maintains a strict safety envelope so I can concentrate on other aspects of the drive.
     
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  5. Doug McC

    Doug McC Member

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    First of all, the DRCC uses not just the radar under the emblem, it also uses the camera, and the sensors for blind spot and the others around the car are all still active.
    Second, your owners manual warns that we should NEVER rely on the system to think for us, because it won’t.
    Third, I have yet to have mine behave the way you describe, and have been in traffic situations just as you describe, and have had the system disengage itself (just as the manual says it will). But then again, perhaps it didn’t disengage so much as the driver was aware of his surroundings and responded accordingly.
    There is plenty of information available on how these systems ACTUALLY operate and it is well worth our time to learn about them.
    Third, the more you take the time to learn about them, the more you will learn just how little most dealerships know about them.
    Fourth, these systems and the cars were not produced in a vacuum. Believe it or not they actually underwent extremely involved testing in real world situations.
     
  6. sam spade 2

    sam spade 2 Senior Member

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    Y'all who have actually observed this behavior should report it to
    the NHTSA and the NTSB.
    It is a safety hazzard.......and there is no GOOD reason for it to work that way.
     
  7. Doug McC

    Doug McC Member

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    Assuming it actually IS working that way, of course.
     
  8. prius16

    prius16 Active Member

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    I can see how that could be an issue.
    Properly, in heavy traffic, if someone wants to change lanes, they turn on their turn signals, and wait for an opening, often by another vehicle, allowing them into that lane.


    With the above said, I realized that I have not noticed that issue - at least not yet.
    There could be a few reasons for that
    1) I have a 2022 Prius Prime Limited, with TSS 2.0 and "Blind Spot Monitor with Rear Cross-Traffic Alert".
    Imho, the Blind Spot Monitor (BSM) works very nicely on my car. I love it - Two Thumbs Up!

    2) When I'm using Cruise Control, I'm often more relaxed mode, and I'm not in a "big rush" to get some where.
    Imho, if I'm in a rush, then cruise control is the wrong thing to use.


    Fwiw...
    3a) I also always have my DRCC set for max distance. That way, I don't stress as much, when there's sudden braking.

    3b) Unlike many Tesla drivers that fully depend on "auto-magic-megaAI-cruise" or what-ever, I'm more aware of the limitations of these types of systems.
    I also got a Limited, specifically since it has a Head Up Display.
    Fwiw, even the fraction of a second that it takes to look down at the dash for the speed, results in many feet of travel at high way speeds.
    At 65MPH, a vehicle travels over 93 feet each second.
    Code:
    https://www.google.com/search?q=convert+65+miles+per+hour+to+feet+per+second 
    Btw, an easy walking speed is about 20mins per mile. Or, 3MPH.
    At an easy walking speed of 20mins/mile, that is still 4.4 feet per second.
    Code:
    https://www.google.com/search?q=convert+20+mins+per+mile+to+feet+per+second 
    3c) Fwiw, there is no way I would trust any automated system in traffic that has "very rapid, very hard braking".
    In other words, common NYC and Boston rush hour traffic.

    3d) It should also go without saying, that none of these system do very well, or even work at all, in many rain, snow, fog, etc conditions.
     
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  9. Doug McC

    Doug McC Member

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    WOW!!!!!!! It is nice to know that there are other intelligent drivers out there!!!!
    OH WAIT! I just noticed the UK. Well, I was hoping you were in the states, but now the surprise at the iq level is less surprising
     
  10. RRxing

    RRxing Senior Member

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    upload_2022-7-2_12-44-0.jpeg
     
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  11. Doug McC

    Doug McC Member

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    THAT’S THE DEFECT!!!!!! Toyota forgot to install that sign on the DASHBOARD!!!!!!
     
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  12. Rapher

    Rapher New Member

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    Hi!
    I did file with the Natl Hwy Traffic Safety Admin. The Toyota dealer tech also indicated that he would file with Toyota. I also filed with Toyota. Since they don't consider this to be a defect but a 'feature' it will likely go nowhere with them. I also sent a note to Consumer Reports. It would be useful if they vindicated what I experienced and wrote about it.
     
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  13. Rapher

    Rapher New Member

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    Hi!
    I agree it is not a good idea to pass on right. I was only testing the system. One other thing about this 'feature' I just discovered. As mentioned if you want to pass on the left and activate the left turn signal the car will automatically begin to accelerate before you make any move to the left lane. This also occurs with a car in the left lane that would block your entry... So here you are accelerating with vehicle in front of you and to your left. Good luck!
     
  14. Rapher

    Rapher New Member

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    Hi!
    In my 2022 version, once the left turn signal is activated, the car will accelerate even if there is a car in the left lane. BTW, I have an XLE with all the bells and whistles safety features. Frankly this acceleration with a car in front and to your left, is not safe! The response to slow down if the car in front of you slows down is simply not safe!
     
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  15. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Well I don't think I tried using it in circumstances where someone was passing me, so I didn't happen to experience that effect.

    I'll never claim perfection but I try to avoid the 3-way combination of passing someone with cruise control active and other peoples' passing maneuvers. Just too busy. In those situations I'll rely on the radar cruise to slow me down to chill out behind somebody else for a while or I'll take full control and drive for a minute.

    In any case I survived the week in the rental and made it home to my own cars unscathed.
     
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  16. bisco

    bisco cookie crumbler

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    the throttle should never be activated by the turn signal without using other nanny tech to detect the carnotchanging lanes with car in front and car on side
     
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  17. Doug McC

    Doug McC Member

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    I have used this system repeatedly in heavy traffic and have never experienced this issue, in fact I have actually had the system reduce speed when someone passes me on the left and is a little too close to me. Hard to see how the problem you describe could occur in my Prius.
     
  18. Doug McC

    Doug McC Member

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    Sounds like “responsible driving” to me. I bet you don’t have the overwhelming desire to text while you’re driving either! ;)
     
  19. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    I like automatic driving aids, but they have to be helping me. The moment I'm doing something to accommodate them comes slightly after the point where I should have turned them off and just done it all myself.

    I've long accepted the idea that the technology only helps sometimes, and that I still have to drive. No points deducted for failing to use cruise door-to-door.
     
    #19 Leadfoot J. McCoalroller, Jul 7, 2022
    Last edited: Jul 7, 2022
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  20. Doug McC

    Doug McC Member

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    Page 326 of the 2022 manual:
    “When the turn signal lever is operated and your vehicle moves to an over- taking lane while driving at 50 mph (80 km/h) or more, the vehicle will accelerate to help to overtake a passing vehicle.”
    Page 336 of the 2022 manual:

    “■Conditions under which the vehicle-to-vehicle distance control mode may not function correctly
    In the case of the following conditions, operate the brake pedal (or accelera- tor pedal, depending on the situation) as necessary.
    As the sensor may not be able to correctly detect vehicles ahead, the system may not operate properly……
    ●When steering wheel operation or your position in the lane is unstable”

    apparently this problem occurs when some “mysterious” force moves the steering wheel to cause the car to move into another lane. ;). :)
     
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