When Radar Cruise Control slows car, do brake lights illuminate?

Discussion in 'Gen 3 Prius Main Forum' started by Coastie, Oct 22, 2009.

  1. Coastie

    Coastie New Member

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    This question came to me as I was bucking stop and go traffic in the Bay Area. Seems like it would be nice if the guy behind me had a warning that I was slowing.
     
  2. qbee42

    qbee42 My other car is a boat

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    I would suspect not. When you lift your foot from the gas, the brake lights to not illuminate.

    Tom
     
  3. PRPrius

    PRPrius Active Member

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    that is a good questions! I know for a fact that Mercedes activates the brake lights when the vehicle automatically applies the brakes. I think the Prius should definetly activate the brake lights if the car uses the brakes to slow down. Granted, most of the time the prius will most likely use the regenerative braking mode.
     
  4. garygid

    garygid Senior Member - Blizzard Pearl

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    If the brake pedal is depressed just a little bit (about 1/4 to 1/2 inch), my P-III + Nav turns on the brake lights.

    If the car is slowing any substantial amount, the brake lights really should come on.
    To test, loosly tape a small strip of paper over part of the 3rd (high) brake light and down over the lower window, and you should be able to see a red glow on the paper strip (in the rear-view mirror) when and if the light comes on.
     
  5. qbee42

    qbee42 My other car is a boat

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    Regenerative braking is the same as any other braking, except for the small amount used to simulate engine drag. I agree that the issue is whether the car slows due to braking or simply removing power. If it is removing power, then no brake lights are needed. If it applies the brakes, then the lights should come on.

    Tom
     
  6. WmDaniel

    WmDaniel New Member

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    This was a concern of mine as well. The break lights do not illuminate in this situation. Think about it like downshifting a standard transmission, using the engine to slow the car. In that case the car slows without activating the break lights.

    Daniel
     
  7. SFBayAreaPrius

    SFBayAreaPrius New Member

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    When the laser or radar cruise on any Toyota slows the car, the brake lights do go on.
     
  8. Tideland Prius

    Tideland Prius Moderator of the North
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    how hard does it have to slow down before the brake lights come on? The same as if you were to drive??

    Sometimes the DRCC appear to just coast so I presume under those conditions, the lights won't come on. It's only when it starts to apply the brakes, then the brakelights will come on. Am I right?
     
  9. swerthei

    swerthei Junior Member

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    It depends. The RCC has two different methods it can use to slow down the car. It can let up on the throttle, for gentle deceleration, or apply the brakes when it needs to decelerate harder, like when you're coming up fast on slower traffic. The RCC decides which to use based on how quickly it thinks you need to slow down. When it only lets up on the throttle, your brake lights don't come on - same as when you take your foot off the gas. When it applies the brakes, your brake lights do come on, just like when you apply the brakes yourself.
     
  10. qbee42

    qbee42 My other car is a boat

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    Does it have a mode to simulate an elderly driver, where it rides the brakes and drives with the left turn signal continuously flashing?

    Tom
     
  11. KFriesen

    KFriesen Junior Member

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    I was driving back from Spokane today on my first ‘road trip’. I thoroughly enjoyed the drive using the cruise technology on my new prime. The same question came to my mind as several times the car braked fairly fast. Are the brake lights coming on to warn those behind me that I am stopping faster than normal... What I really liked was how the cruise worked in the mountains. In the past you just couldn’t use cruise at all on curvy roads. I noticed that my car would anticipate the sharp corners ahead of time and slow the vehicle before getting to the corner. Very impressive! I found it would bring me to a complete stop a number of times and actually start moving with the traffic as it started up. Sometimes I just needed to tap the accelerator to get it going again! Amazing!
     
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