Lane keep assist

Discussion in 'Prime Audio, Electronics, and Infotainment' started by bruceha_2000, Apr 8, 2019.

  1. bruceha_2000

    bruceha_2000 Senior Member

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    It is my understanding that besides the audio and video warnings there is supposed to be a "tug" on the wheel. True? I don't feel a thing. And if true is it adjustable somehow? Like it could actually pull the car back into the lane? I am 100% a "signal to change lanes" person.
     
  2. davecook89t

    davecook89t Active Member

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    You've come across one of the issues that has given rise to one of the more common complaints many of us have about the Toyota Safety Sense system. Although I was not privileged enough to own a Gen 3 Prius with what was then called the Lane Keep Assist, I've been told by some of those who did own a Gen 3 car with the Technology Package which included LKA, that that implementation of "self steering technology" was much more aggressive (and therefore more useful) than the current watered-down version. The only people who don't have a complaint about the currently available Lane Departure Warning system seem to be those who are dead-set against any type of "auto pilot" on principle. They may have some valid points about such systems encouraging inattentiveness at the wheel, but I think most of us who bought the Gen 4 car would have appreciated a better use of currently available technology. The thinking of some is that Toyota backed off of making the more aggressive LKA a standard feature because they were afraid of lawsuits if people came to rely upon them too much and that led to more accidents. I think that was a cowardly thing to do.
     
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  3. Tideland Prius

    Tideland Prius Moderator of the North
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    There's no Lane Keep Assist (LKA) in the Gen 4 or Prime. It's officially labelled Lane Departure Warning with Steering Assist. What's the difference, you ask?

    LKA actively keeps you centred in the lane by making constant adjustments. It's like the front passenger having their hand on your steering wheel, making small adjustments to ensure you're centred. This is an active system.

    LDW w/ SA is a semi-active system. It'll allow drift within your lane (so it doesn't actively keep you centred). However, if it sees you drift out of the lane, it'll beep at you. There doesn't seem to be a rhyme or reason where the SA will activate and when it won't. I've seen it tug at the wheel before I cross the line (esp. if I'm passing a cyclist and I'm hugging one side of the lane to give the cyclist clearance... I can feel slight resistance towards the outside of the lane... i.e. it's making it "harder" for me to leave my lane). Other times, it will let me leave the lane and just beep at me. Yet other times, it will let me cross the line, beep, then correct me. Anytime the steering wheel correction is active, you'll see a green steering wheel icon on the dash.
     
  4. Solar Powered Prime

    Solar Powered Prime Junior Member

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    Thanks for bringing up this question again and thanks for the answers. I have intentional left go of the steering wheel on highways with clearly marked lanes that have a curve in them and I have never felt any correction. Plenty of beeping. We asked the dealer and did not get a satisfactory answer.
     
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  5. robertjackson17

    robertjackson17 Junior Member

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    Comma.ai and their OpenPilot seems to be what LKA should (or could) have been. Look for the "My Prius Prime Drives Itself" thread in the "Prime Accessories and Modifications" subforum.

    My Prius Prime Drives Itself | PriusChat

    Edit: I have no affiliation with the company. I do have their system in my Prime. It's fantastic!
     
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  6. Flaming

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    You can have the LKA warning ''beeps'' without having the nudges on the steering wheel , make sure the steering wheel assist option is also enabled . When it's working you can see a small green steering wheel icon in the dash when the car try to correct the direction.
     
  7. jerrymildred

    jerrymildred Senior Member

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    So you only see the steering wheel icon when it actually nudges you? That would explain why I have it turned on but see no icon. I don't know why, if I'm drifting off the road and the car is trying to get me back, I would be looking at something other than the road. I have mine enabled and have tried several times to see if it would nudge me back, but it never has. Is it because it won't nudge you if you cross over deliberately? I don't think I can do it by accident. And how does it know? This feature is one of my biggest puzzles with the car.
     
  8. Flaming

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    The icon turn on just a few seconds ...so yeah not easy to spot...its in the far right part of the dash around the cruise control icon. I also have noticed that the car is able to detect if you are holding the steering wheel firmly or not. If you are holding the wheel too firmly the steering assist may not turn on because the car think that you really want to cross a line.

    There is multiple conditions to make it work or not. Line quality , Lightning , Sun glare in the camera or even the width of the road ...if its too small = not working


    Posted via the PriusChat mobile app.
     
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  9. jerrymildred

    jerrymildred Senior Member

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    Thanks. I knew where to look. It just doesn't seem to do much. But in reality, it's academic since I'm one of those weirdos who watches where he's going. :D I tried it on a friend's Honda and that nudge had some authority to it.
     
  10. Flaming

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    I wish i knew the full details of the feature ,sometime the LKA don't even beep or display a warning but i feel a strong pull on the wheel and the green icon is blinking..happen often in sharp curves......ah oh ..now that i think of it i have the LKA sensibility set to high maybe it affect the steering assist force too ? I do not know ;)

    Posted via the PriusChat mobile app.
     
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  11. bruceha_2000

    bruceha_2000 Senior Member

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    It shouldn't do anything if you have your turn signal on. Otherwise it should at least beep though often it seems like I've already crossed the line by a foot before that happens. I'll see what my sensitivity is set to, I would ASSUME I would have chosen the most sensitive setting since I would LIKE it to warn me as it pulls the car back into my lane. Sounds like that pulling back just isn't going to happen though.
     
  12. jerrymildred

    jerrymildred Senior Member

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    It can't and it doesn't.

    And that's all it's ever done with one possible exception on a test where I think I felt a little something.

    Yes, I have sensitivity set to max. I'll be able to test it more thoroughly when we take our vacation trip in a few weeks. Honestly, it's not a big deal to me other than the curiosity factor. The only times it's ever beeped is a few times when I deliberately cut the corner. I don't wander out of my lane.
     
  13. Solar Powered Prime

    Solar Powered Prime Junior Member

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    Doesn't anyone from Toyota read these questions? As knowledgeable as people are in this forum, I would really like someone, who knows how it is actually supposed to work, to explain this mysterious feature. It doesn't make me happy when different owners have such different experiences. I would expect it to perform the same on all Primes, or at least we should all know how it is supposed to work, so we can get ours fixed. Our dealer doesn't seem to know either. I do get that we all assume that it will help us from drifting into another lane. Ours doesn't. We have never felt the car nudge us back in the lane. It does beep.
     
  14. bruceha_2000

    bruceha_2000 Senior Member

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    The beeping does alert you that you are leaving your lane (assuming there are adequate lines visible) so that is a help. It just isn't doing anything to correct your error which is unfortunate. Coupled with the adaptive cruise control, it could be a nearly self driving car on interstates.

    I don't know that anyone from Toyota reads these forums. I assume not. I know that the heated seat switches on my daughter's 2010 are nearly impossible to see/reach and I would assume that has been mentioned many times yet when they did the Gen IV redesign, they kept them in the same place. Not sure why they finally smartened up and moved them in the 2019's. At least they got rid of the horrible arch from the Gen IIIs and moved the shifter back up onto the dash. You don't touch the thing more than a max of 4 times on most drives, often just 1 or 2 and they are at the beginning and end of the drive. Why put it in the way of other controls?
     
  15. Tha_Ape

    Tha_Ape Member

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    I have both a gen 3 Prius with adv tech package and a Prime.

    The Gen3 is WAY better at steering around curves. It's nothing you can sit back and watch, but it definitely keeps you in the lane better than the prime.

    Gen3 only activates above 45mph and it needs nice lines to look at. I got the Prime hoping it would be amazing in Lane Keeping. The adaptive cruise is so much better on the prime (goes to a full stop vs the Gen3s >25mph restriction.

    I'm still pleased with the purchase, but Toyota took a step backwards with Level 2 autonomy with respect to lane keeping. Honestly, software updates could fix it, but I suspect they are worried about liability.

    Also i just got the prime so maybe i haven't experienced it yet, but the pre collision system in the gen3 reels the seatbelts in if it thinks a collision is imminent. Ive only had it happen a handful of times on the gen3, but never in the Prime. I live near DC so it's Just a matter of time before I find out ( usually triggered by someone cutting you off and braking a little).
     
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  16. jb in NE

    jb in NE Senior Member

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    The Prime appears to do this only if a collision has been initated. I think this is a better system - I don't want my seatbelt retracting while I'm still trying to avoid a collision. The seatbelts only need to be tensioned when you need them to be, no sooner. From p.31 of the Prime owner manual:

    "The pretensioners help the seat belts to quickly restrain the occupants by retracting the seat belts when the vehicle is subjected to
    certain types of severe frontal or side collision or a vehicle rollover"
     
  17. fuzzy1

    fuzzy1 Senior Member

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    Considering how many people are abusing these driver assist systems, treating them as a higher level 'self driving' system than they really are, it is probably a good thing to dial back their activity in order to reduce liability. Enforce a certain degree of driver engagement until the true self-driving systems are ready for prime time.
     
  18. royrose

    royrose Senior Member

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    According to the Toyota website, both the Prime and regular Prius have Toyota Safety Sense P while newer model vehicles like the new Rav4 and Corolla (hybrid and gas models) have Safety Sense 2.0.

    Safety sense P, as stated above, has LDW (lane departure warning) while Safety Sense 2.0 has LTA (lane tracing assist) which sounds a lot like what was previously called Lane Keep Assist. So it seems this was dropped from Gen 3 to Gen $ Prius, then put back in (maybe Improved) for later vehicles.

    So, I'm not sure I would call the safety features in the Prime "level 2". I do think it is confusing because Safety Sense P was supposedly an improvement over the original Safety Sense.

    Here is a description of LTA from the 2019 Rav4 Hybrid manual: "When driving on highways and freeways with white (yellow) lane lines, this function alerts the driver when the vehicle might depart from its lane or course* and provides assistance by operating the steering wheel to keep the vehicle in its lane or course*. Furthermore, the system provides steering assistance when dynamic radar cruise control with full-speed range is operating to keep the vehicle in its lane."
     
  19. Tideland Prius

    Tideland Prius Moderator of the North
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    Lane Tracing Assist allows the car to follow the car in front if it cannot detect the lane lines. That's the major difference between LTA and LKA.
     
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  20. royrose

    royrose Senior Member

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    So, did Toyota discontinue LKA until they could enhance it? I'm curious whether Toyota did this with any vehicles besides the Prius.

    My understanding is that the capability of following a car is part of the steering assistance when the radar cruise control is active.
     
    #20 royrose, Apr 29, 2019
    Last edited: Apr 29, 2019
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