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Rear collision system questions

Discussion in 'Gen 4 Prius Main Forum' started by Gen 2 Tom, Jun 9, 2016.

  1. Gen 2 Tom

    Gen 2 Tom Active Member

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    I finally had the system beep, as I came up rather fast on almost stopped cars. I'm not sure if I was on the brakes or just hit the brakes as it beeped. I didn't feel the system apply any brakes.

    Would it apply more brakes even though I was on the brakes? How long after the beep would it try stopping the car? What sensor does it use for this, radar or camera.
     
    #1 Gen 2 Tom, Jun 9, 2016
  2. Mister MMT

    Mister MMT Active Member

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    Could it be you mean the pre-collision system (PCS) of the TSS?

    .

    As you probably know, the Rear Cross Traffic Alert, uses radar sensors mounted on the rear corners and is active when backing out from a parking spot.

    2016 Prius - the next generation of Toyota's technology ambassador - Toyota

    Jan
     
    #2 Mister MMT, Jun 11, 2016
  3. DonDNH

    DonDNH Senior Member

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    Sonar sensors. Radar sensor is for DRCC and is behind the Toyota logo on the front of the car.
     
    #3 DonDNH, Jun 11, 2016
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    RCTA uses millimetre wave radar mounted behind the rear bumpers. The sonar sensors are for ICS and SIPA.

    upload_2016-6-11_12-35-16.png

    upload_2016-6-11_12-35-56.png
     
    #4 Tideland Prius, Jun 11, 2016
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    The system will do a number of things

    1. Beep and flash "BRAKE!" on the screen (which you heard)
    2. Prime the brake pads by moving them closer to the discs, reducing the distance and time needed to apply the brakes
    3. Prep ABS and Brake Assist for when you eventually hit the brake pedal

    From here on, there are two versions

    Version 1: You respond and hit the brakes
    • Depending on how fast you respond (i.e. how fast you lift off the accelerator and how fast you depress the brake pedal), Brake Assist may or may not come to your assistance. Brake Assist just helps you apply greater braking force if the computer determines you're performing an emergency brake but you're not pressing the brake pedal hard enough.
    • Assuming you're braking hard enough from a higher speed, Pre-Collison Seatbelt will then tighten the front seatbelts so that your upper body doesn't move forward under braking. This means you're properly seated to manoeuvre around the object if necessary or should the worse happen, it minimises the chances your face will hit the airbag.
    Version 2: You don't respond and a collision is imminent
    • If the car determines a collision is imminent and you didn't respond, Pre-Collision Braking will take over and apply the brakes fully to bring the car to a halt. PCS reduces the speed by up to 40km/h (25mph).
    • Pre-Collision Seatbelt will also tighten the front seatbelts.

    So to answer your questions

    1. Yes it will apply more braking force if it thinks you're not braking hard enough (Brake Assist. This is standard on practically all new cars)
    2. How long after the beep? It depends on how fast you're approaching the object.
    3. It's using the radar mostly. The camera is used for pedestrian detection (and lane departure alert) but I'm not sure if it's also used for vehicle detection for the PCS.
     
    #5 Tideland Prius, Jun 11, 2016
  6. David Beale

    David Beale Senior Member

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    See, the tin foil hatters were right! Big Brother IS watching! ;)
     
    #6 David Beale, Jun 11, 2016
  7. ETP

    ETP 2021 Prime(Limit),24 Venza Limit,B52-D,G,F,H

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    So does it stop the car before impact? Sounds like no to me.


    Also does the rear cross traffic system apply brakes?

    Tin foil is required for all pedestrians for this car to work correctly.
     
    #7 ETP, Jun 12, 2016
  8. alanclarkeau

    alanclarkeau Senior Member

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    The demonstrations have all shown that it DOES stop the car before impact. But NOT in reverse - it just alerts you to cross traffic.



    -> the demonstration starts at 2:20.
     
    #8 alanclarkeau, Jun 12, 2016
    DonD and ETP like this.
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