Limitations of "radar cruise" augmented driving

Discussion in 'Prime Main Forum (2017-Current)' started by satsuke, May 24, 2021.

  1. satsuke

    satsuke Junior Member

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    Has anyone explored the limits of the self driving functions on the 2021 prime limited?

    I just tried it and it seems almost useless as is .. at least I know that it'll keep distance and in your lane on well marked highways. But can't realistically do gentle curves or anything like that.

    I say useless because it seems like I'm trying to fight against it when needing to take a curve or other thing that isn't straight / flat road.

    even on straight/flat road on cruise control, it seems to do a funky slight over correct left, than overcorrect right back and forth.

    Am I missing something?

    (Haven't had to use the automatic braking, thankfully).
     
  2. icharis

    icharis New Member

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    I have only had the car for a few days but it acts like all of my other cars with the same feature.. I find it best driving it on highways with bumper to bumper traffic where I just set it and chill and wait
     
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  3. fuzzy1

    fuzzy1 Senior Member

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    The Prime doesn't have self driving. Period. Full Stop.

    It does have a number of driver assist features, but calling them "self driving" is just asking for fatalities. Just as has happened repeatedly with Tesla drivers abusing their more advanced but mislabeled driver assist functions.
     
  4. satsuke

    satsuke Junior Member

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    Or you could answer the question
     
  5. wjtracy

    wjtracy Senior Member

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    Assuming it is like a 2020 RAV4HV, it will make the turns via LKA Lane Keep Assist button.
    You have to have hands on wheel, or an alarm sounds.
    In the menu you have some choices to fine tune to your liking.

    I think what you are saying is it drives differently than you do, so you have to steer.
    it drives a little different than me too. The thing I find most different than me, is the radar cruise control starts braking a lot later than I would. I would anticipate earlier when approaching stopped vehicles.
     
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  6. PiPLosAngeles

    PiPLosAngeles Senior Member

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    The LKA is easily fooled by highway exits and always veers to the right. It also "ping pongs" between the right and left lane markings. I can't use it most of the time because I'm genuinely fearful of getting pulled over for impaired driving.
     
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  7. Salamander_King

    Salamander_King Senior Member

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    What self-driving functions on 2021 prime limited are you talking about? It does not have one. I have read that Lane Departure Alert (LDA) with Seering Assist and LANE TRACING ASSIST (LTA) of TSS2.0 is an improvement over the LDA of TSS1.0 found in pre-2020 PPs, but that is still not intended for the self-driving. Personally, I found both Radar Cruise (DRCC) and LDA on both 2017 and 2020 PP worthless for my daily driving. The Radar Cruise was convenient for some long-distance highway drives, but I really didn't use it on my daily driving.
     
    #7 Salamander_King, May 24, 2021
    Last edited: May 24, 2021
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  8. Tideland Prius

    Tideland Prius Moderator of the North
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    Yes. Because you’re going into this thinking it’s self driving. It’s not. They are all driver assist systems.

    The Prime’s Lane Departure Warning w/ Steering Assist is aptly named. It is not “Lane Keep Assist” like the previous generation or other systems from other manufacturers that have “lane keep” in them. There are two types of lane departure/keep systems. Tesla’s Autopilot is the latter (like Honda’s LKAS or Toyota/Lexus LKA). The Prime only has LDW

    He did. You ask if there was something wrong with the Prime’s self driving features. There isn’t because they don’t exist.
     
  9. Washingtonian

    Washingtonian Senior Member

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    Over the years I have owned many cars with cruise control. The radar assisted cruise control on my PP is a vast improvement over all of them.
     
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  10. icharis

    icharis New Member

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    2021 prime has lane track and it will make turns on properly marked roads

    I did a test and drove it with pretty much hands off, just touching the steering wheel when the alert would appear to keep hands on for a slight second. It actually performed really well. As other posts have said its not self driving but it performs as expected.

    This was my route.. You can look on google map The forum wont let me post a link



    upload_2021-5-24_11-29-26.png
     
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  11. DukeofPrime

    DukeofPrime Junior Member

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    I think the lane keep function generates input into the steering to make sure you're holding on. It does seem like you're fighting the car a bit (at least to me). I find it useful if I have to monkey with something in the car (open a bottle of water, fuss with the radio). Prior to this, I'd steer with my knee. It will track a gentle freeway curve. I mostly turn it off as I'm usually paying attention so I'm not concerned with drifting out of my lane.

    The radar cruise is way better than it was in my 2004 Sienna. Floored it when the lead car switches lanes, slammed on the breaks if some one cut in front. It's still not perfect, but I find it quite useful for semi-crowded highway driving. At least you can disabled it, too.

    SM-N981U ?
     
  12. Maggy Field

    Maggy Field Junior Member

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    @Washingtonian I agree with your statement, I use it 80% of the time. My only issue occurs when driving at 40 mph or more with a car a few hundred yards in front of me. If that vehicle slows and starts a right turn to exit the pavement it causes sudden braking as the system thinks the car has stopped in my lane. IF I remember, I quickly disengage cruise, or change lanes to avoid this. Of course it would require another level of sophistication for the system to recognize that the vehicle in front of me will be clear by the time I get there, and I don't think it is realistic to expect it to. To me this is another example of the 3D problems our minds are so good at solving but machines are not, especially when they require understanding the intentions of another human being.

    My other minor gripe involves the difference in cruise control between our 2017 Sienna and the 2021 Prime Limited. On the Sienna I hold the cruise stick down to reduce my set speed as the vehicle "coasts" down to the speed I want. When I release it the cruise resumes at the new lower speed. On the Prime, holding the cruise stick down rapidly decrements the electronic set point, regardless of the vehicles actual speed. If I forget and operate the cruise in accordance with my habit on the Sienna I can find the car braking hard to get to the new set point which turned out to be much lower than I intended. Since we have both vehicles and likely will for many years, this problem is not going away for me.

    The LTA is best saved for long drives on a well marked interstate, but the edge warnings with a "nudge" are quite helpful at times.

    I am very satisfied overall with the driver assist and general safety features of the 2021, and I use them often.
     
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  13. sam spade 2

    sam spade 2 Senior Member

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    Well he kind of did, and you might realize that if you would chill and think about it for a minute.
    You are expecting too much from the "features" that you are talking about.
    They are NOT "self driving" features.

    While I don't have "lane keeping ASSIST" on my Toyota, I find it more annoying than useful on my Ford Focus Hybrid.
    The other features, however, do an excellent job for what they were intended.

    Dynamic cruise and automatic braking and/or "crash alert" are very useful features that you should have enabled.
    Lane keeping, not so much.
     
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  14. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    Your owner's manual?
    As stated above...the meaning of the word "self driving?"

    PP's have some features to help with the driving task but they are in no way intended to be self-driving, and some of their "safety" features may lead to the vehicle being LESS safe if not properly driven.

    There was a famous airplane crash in 2009 where some very highly trained folks let a nearly perfectly functioning jet aircraft fly itself into the water, killing 228 people.
    This was CAUSED by an over-reliance on "safety features" and not knowing when to drive the vehicle.

    We're not trying to insult you or hurt your feelings, and you MAY want to check with the people who designed and built your car before you bet your life (and other people's) on your car's "automatic braking" system, because it may not be as reliable at highway speeds, and in certain weather conditions as you may think that it is.... ;)
    Automatic braking sometimes brakes for nothing
     
    #14 ETC(SS), May 25, 2021
    Last edited: May 25, 2021
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  15. PiPLosAngeles

    PiPLosAngeles Senior Member

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    I achieve the same result in the Prime by pulling back on the cruise control lever to cancel and then pressing down to set when it coasts to the right speed.

    Although it leaves much to be desired, I do turn it on when I'm going to do something which might make me more distracted than usual. It's helpful for those cases.
     
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  16. Washingtonian

    Washingtonian Senior Member

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    Not sure if the '21 is different from the '17, but to increase or decrease the set speed I just tap it one time for each MPH. For example, if set at 68 and I want to reduce it to 65, I just tap it down three times.
     
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  17. PiPLosAngeles

    PiPLosAngeles Senior Member

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    That gets difficult when you want to go from 65 to 40, or some large offset.
     
  18. Washingtonian

    Washingtonian Senior Member

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    Is it difficult to touch the end of it to turn if off; brake or just slow down to 40 and turn it back on? Of course the next generation will be voice actuated and you will just say "Toyota - Set cruise control to 40!".
     
  19. Mendel Leisk

    Mendel Leisk Sand Pounder

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    Can you use smart cruise in “dumb” mode, ie*: per traditional cruise? At least then you know what it will and won’t do, reliably.

    *I’ve used “ie” for donkey’s years, never looked it up:

    https://www.etymonline.com/word/i.e.
     
  20. Maggy Field

    Maggy Field Junior Member

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    I suspect the answer to your question is no, but I can't be sure I understand your question. What would "dumb" mode look like?
    I do know exactly what it will do in each car, my irritation is that the same control inputs result in different results between them.

    The simplest solution is to modify my behavior to the common denominator, i.e. always bump the cruise off and re-engage it when I have coasted or braked the car down to the speed I want it set at, as first suggested by PiPLosAngeles.
     
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