Euro model's AHS Adaptive high beam system

Discussion in 'Prime Main Forum (2017-Current)' started by GT4Prius, Apr 19, 2017.

  1. RCO

    RCO Senior Member

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    Well, if you have got the auto lights selected with the lower fascia button (next to the HUD) then the camera will notice street lights and auto dipped beams will be applied. Not sure if that is the case without auto being selected. Not sure when I'll be out after dark next, but if I remember, I'll test it.
     
  2. Prius Maximus

    Prius Maximus Senior Member

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    My understanding is USDOT can't figure out a standardized test for adaptive beam headlights, and without test results they won't approve any of them.
     
  3. mr88cet

    mr88cet Senior Member

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    Ah, pretty cool! As I recall, Teslas have a kinda-sorta similar feature.

    Unfortunately, I don't know the answer to the OP's original question.

    Another feature that I gather is available on the EU version but not on the US version is:
    I think I read somewhere that there was some rollover-related US law Toyota couldn't meet with it. I don't know of course, but I wouldn't be surprised if Toyota just didn't expect enough US sales of the solar roof to make it worthwhile to submit a thus-equipped P.Prime for roll-over compliance testing.


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    #23 mr88cet, Apr 19, 2017
    Last edited: Apr 19, 2017
  4. EV Life

    EV Life Junior Member

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    If auto high beams button is not activated and high beams are on, they will stay on even if there's an oncoming car. I was blinding someone for a good second before I realized that the feature was turned off. If you press the auto high beams button, you still have to turn on high beams from the signal lever for it to function.
     
  5. RCO

    RCO Senior Member

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    I agree with all you just said, but -- when set and on main beam you drive into an area with street lighting, my headlamps automatically dip. In future, I want to check if they do that even when auto-dip isn't selected. (y)
     
  6. civicdriver06

    civicdriver06 Active Member

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    Yes i read that too,but how do vehicles with a near enough all glass roof (Model 3) get approval ?
     
  7. mr88cet

    mr88cet Senior Member

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    Again, I don't remember the details of the roll-over concern, but if it's top-heaviness, then certainly no Tesla car would ever see that problem with thousands of pounds of batteries in the floorboard. The P.Prime's battery is mounted much higher, although certainly not "high" by any means.


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  8. unicorn

    unicorn Member

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    I guess, 40mph is a good idea for the EU countries with the urban areas speed limit 31mph (50 km/h). A lower speed would be distracting in city/villages (and it doesn't know where you are).

    On the other hand, the AHS is working at speeds below 40mph, e.g., if you are crossing the villages (see French video above). Finally, if you start in dark country lane, then you have to reach 40mph and slow down.
     
  9. RCO

    RCO Senior Member

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    Perhaps that's what is happening to me, though I'm not sure I always drop to the speed limit whenever the law demands it. See #21 above.
     
  10. Trollbait

    Trollbait It's a D&D thing

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    I've only seen the roll over reason in the form of a rumor. The closest official one from a Toyota spokes person is simply that Toyota didn't think Americans would be willing to pay for the option with our cheap energy. In the Prime's home country, it is $3000 on top of the price for a higher trim.
     
  11. GT4Prius

    GT4Prius Active Member

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    Low speed and urban areas aren't necessarily the same thing. The car should be able to detect urban areas with street lighting without just relying on low speed IMHO.

    My question is to do with my experience in nonurban areas with no street lighting where I would normally use high beams but the car is not turning AHS on for some reason which is not explained by the manual, (until I hit 40mph).

    (Even though all the required conditions stated in the manual are met, that is AHS switch on, column stalk forward in high beam position and at night in darkness).

    Posted via the PriusChat mobile app.
     
  12. RCO

    RCO Senior Member

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    Not sure I can give a definitive answer, sorry. However, one thing I've noticed on my Business Edition is that even when the stalk is in the dipped position when the AHS is selected, first time I push the selector forward to main beam the system activates. Just like that! (With apologies to Tommy Cooper).
     
  13. unicorn

    unicorn Member

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    Well, I don't know if AHS in your car is working or not.

    But personally I'm satisfied with the AHS functionality in French video:
    0:14 - dark lane, AHS on, a car is starting with wide low beam
    0:30 - speed probably 40mph, low beam is switched to high beam

     
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  14. RCO

    RCO Senior Member

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    Not sure what was said and couldn't see any road speed, but the car was in fact a Prius Prime. Can you eliminate coincidence for your nominating 40 mph as a trigger point?
     
  15. unicorn

    unicorn Member

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    Nice homework ;)

    Firstly, the trees on the road sides is possible to see much better at time 0:30 (low beam switched to high beam).

    Secondly, let's approximately calculate the speed at time around 0:38 using the markings on the road, see the French standard: Markings on the Road - Americans in France
    If you four times slow down the youtube video then it's possible to count the central markings on the road:
    0:38-0:39 -> one second ~ (10m+3m+10m+3m) --> speed ~26mps = 93.6 kmph = 58.2 mph (approx.)
    If we assume the linear acceleration for the time interval 0:14-0:38 then the speed at 0:30 is the following:
    (16/24) x 58.2 mph = 38.8 mph ~ 40 mph

    :D I guess that a driver from video will laugh from my calculations.

    Back to AHS. In video is possible to see that AHS high beam is working below 40 mph as well:
    2:40 - entering village with high beam
    2:44 - shadowing the area where is a vehicle
    2:53 - actual speed (54 kmph = 33.5 mph) is measured on the right side
    2:54 - left side of high beam is switched on, etc.


    The question is: What's the lowest speed for high beam?

    Finally, in the EU Manual is noted: "Do not rely on the Adaptive High-beam System. Always drive safely, taking care to observe your surroundings and turning the high beam on or off manually if necessary."
     
    #35 unicorn, Apr 20, 2017
    Last edited: Apr 20, 2017
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  16. GT4Prius

    GT4Prius Active Member

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    Thanks. It's a valid question. I was sure last time I drove it at night on unlit roads. But I will check again next time and make careful tests and observations.

    Posted via the PriusChat mobile app.
     
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  17. GT4Prius

    GT4Prius Active Member

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    Typical Toyota manual caution re switching to manual. I don't think it should be necessary except in very rare circumstances.

    Also the switch for manual mode is quite low on the dashboard and I reckon it's more designed or at least safer to be used when stationary and not one I would want to use often while driving.

    Posted via the PriusChat mobile app.
     
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  18. pakitt

    pakitt Senior Member

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    I only know that the AHB (automatic high beam) on the Gen4 doesn't work well at all - I get flashed often as the algorithm is too aggressive and keeps the high beam on, even when clearly it should be off as a car approaches. I need often to turn high beam off myself to avoid blinding others.
    It is essentially off most of the time, like the Road Sign Assistance. Totally useless in EU highways where trucks have (by law) stickers showing the max speeds they can reach on the highway and regional roads, and the RSA simply reads them as valid signs. Even not recognizing that their size does not change according to the relative speed of travel. E.g. If am driving 130km/h and the truck at 80km/h, the sign will increase its relative size in the image captured by the camera, at 50km/h and not 130km/h it were planted on the ground. The RSA system has not a clue and reads blindly everything with no logic.
    It is really sad that RSA and AHB do not work well at all and I need to keep them off.

    PS: the Gen4 Prius sold in Germany, where the sun always shines, doesn't offer rain sensor not even as an option on the 2 (of 3) lower trims. It is standard only on the most expensive 3rd tier trim. Like as if the TSSP doesn't need a clean windshield to operate the camera sitting behind it.....!
     
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  19. RCO

    RCO Senior Member

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    Regarding the Toyota manual, I believe they mean by manually selecting dipped or main beam. FWIW, I am usually quicker to respond than the car's automatic system except on long straight roads.
     
  20. unicorn

    unicorn Member

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    Honestly, I'm very satisfied that you've found it as the reliable and clever system. It really brings more safety. (y)

    In video above we can see probably the worst scenario regarding to dazzling effect (the village on horizon with a tall lorry coming) but the AHS has worked satisfactory. On the other hand, if you know the village then it would be better to switch to low beam. That's why I've put the Toyota caution.

    Switching to low beam should be easy according to EU Manual (pp.347): "Pull the lever to the original position. The Adaptive High-beam System indicator will turn off. Push the lever away from you to activate the Adaptive High-beam System again."
     
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