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Dynamic Radar Cruise Control

Discussion in 'Gen 4 Prius Main Forum' started by David Beale, Jan 22, 2016.

  1. David Beale

    David Beale Senior Member

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    AKA "radar cruise" or DRCC. For those who haven't experienced it.
    I have a Gen 3, 2012, so my comments are skewed by that, but the new Gen 4 system is very similar.

    Well, I'll start right off by saying it's great! I use it all the time in the city, heavy traffic or not!
    Because it monitors what's in front of you using cruise in traffic is no longer nerve racking. The car never gets into "iffy" situations. In fact, it's so conservative I find -that- frustrating.
    I set the speed I'm comfortable with, usually a few km/hr over the limit, and the car adapts to traffic.
    The Gen 3 system cancels automatically when the speed gets below about 30 km/hr, and the Gen 4 won't cancel until you stop.
    If you want to pass someone best practice is to cancel cruise, pass, then resume (hit the lever up). But you can pass with the accelerator while in cruise. It doesn't seem to panic and use the brakes.

    There are "warts" of course. A large truck in the lane beside you can cause the cruise control to slow, though that's not too common. What IS common and bothers me is the vehicle turning right, pulled off into the turn right lane. The cruise often slows, as it appears to "capture" that vehicle's signature as it moves into the turn lane. That forces me to step on the accelerator. This doesn't affect the cruise control, it just speeds the car back up and once even half past the slowing vehicle the cruise recovers "sanity" and continues on.

    Be aware if you're coming from a Gen 2 or other car that the cruise in the Gen 3 and Gen 4 can use the brakes to maintain the set speed. If you are driving along on cruise and the speed limit drops you -can- just hit the lever down multiple times to set the new lower speed. If you do this quickly, before the car slows, it WILL use the brakes. Just hope the guy behind you is awake! (happened to me driving Pearl S home when I picked her up at the dealer - and yes, luckily the PU driver behind me WAS awake! ;) Best practice to slow is to cancel cruise, let the car coast down, then set it at the new speed.

    I currently have PCS (Pre-Collision System) turned off. It uses the radar module the DRCC uses. I turned it off because of the warning in the manual that it could interpret things like bridge expansion joints as a collision object and apply the brakes. Not good in rush hour traffic!! I may turn it back on this spring to see if it actually does make that kind of mistake.

    So if you were wondering about the cruise in the Gen 4 and that was affecting your decision to purchase or not, now you know!
     
  2. BigFan

    BigFan Member

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    Thanks for sharing. I spent about 45 minutes playing with DRCC and was impressed. Just for fun I had it active as I approached a red traffic light and sure enough it brought the car to a complete stop (not because the light was red but because the car in from of me slowed and stopped). My Gen-2 has the traditional cruise control and DRCC is a welcomed addition. I look forward to trying DRCC on an actual highway in the near future.
     
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  3. krmcg

    krmcg Lowered Blizzard Pearl Beauty

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    I have the dynamic cruise control on this Prius and on a 2014 Avalon Hybrid that I drive on road trips. I really like the feature and use it any chance I get. I chalk it as a premium safety feature.
     
  4. Tideland2005

    Tideland2005 Member

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    Dynamic cruise control is very cool...
    But, I have to buy a package that has
    a sun roof to get it in the Gen 4.

    ( i very much dislike adding weight to the
    roof of ANY car)

    Next year, perhaps the package bundles
    won't be so peculiar.........
     
  5. MrBillTulsa

    MrBillTulsa Member

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    TL2005, I believe I am correct when I say that a GEN4/4T/PCP has DRCC without a Sunroof. If I am mistaken about this, I need to know it SOON.

    :eek:
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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  7. BigFan

    BigFan Member

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    I believe DRCC is part of the ATP package, which is standard on the Touring models (options on the non-Touring 3/4). I do not think PCP has any direct bearing on DRCC, but the Visual table pointed to above has all the details.
     
  8. TheChosenOne

    TheChosenOne Member

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    I am scared of continuing to use DRCC. I had it on for 20 minutes and decide it isn't for me, at least for now. First time using any kind of cruise control in a car. First of all it gave me worse MPG than if I drove myself. Second, the cruise control was turned off a few times by itself and I had my foot on top of the brake, not on, the whole time just in case something might happen. I had to brake myself those 3 times the car turned off cruise control on its own and I could've crashed those 3 times since I was in traffic. When it turned off I think the message said there was no car detected in front of me but there clearly was and it was 10 feet in front of me.


    Does 4T with PCP brake on its own at any speed if I am about to hit a car or is it just the lane assist that turns off traveling at less than a certain speed? I don't remember which one it is but I've had several messages saying something was turned off due to me traveling at less than a certain speed.
     
  9. MrBillTulsa

    MrBillTulsa Member

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    ChosenOne, am I correct in recalling that some of your DRCC testing was done during inclement weather? DRCC can and often does turn itself off during periods of rain, fog, snow, and etc.

    :eek:


    I am remiss in not checking Visual Tables of Gen4 Package Combinations immediately before posting my last comment above - thank you for your corrections. Having now checked the tables again, I see that Trim 4T includes DRCC as standard equipment, while the Power tilt/slide Moonroof is not offered. Is that not correct?

    :eek:
     
    #9 MrBillTulsa, Jan 22, 2016
    Last edited by a moderator: Jan 22, 2016
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    With DRCC am I right that you can switch off the DR, just use the CC? Could be times for both.
     
  11. BigFan

    BigFan Member

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    You are correct. If the “ON-OFF” cruise control button is pressed and held for 1.5 seconds or more, the system turns on in constant speed control mode (vs the .Vehicle-to-vehicle distance control mode, i.e, DRCC).
     
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  12. 155

    155 Member

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    My 2016 4 Touring has DRCC and no Moonroof, so yes, that is correct. DRCC is standard on the 3 Touring as well, which also doesn't have a moonroof.
     
  13. Tideland2005

    Tideland2005 Member

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    Oh yeah, you guys are right... Thanks for straightening
    that for me.

    Steve

    l stand corrected, but has more to do with orthotics.
     
  14. Tideland Prius

    Tideland Prius Moderator of the North
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    Just an addedum for Gen 4 owners - Your DRCC is full-speed DRCC (while the Gen 3 will disengage under 25mph and will erase the speed memory under 10mph or to put it another way, you can resume DRCC between 10mph and 25mph on the Gen 3).

    On the Gen 4, you can use DRCC in traffic right down to a full stop at a traffic light IF there is someone in front of you (it will not stop if you're the first car at the light!). When the traffic starts moving again, push up on the stalk (RES) to resume or quickly tap the accelerator. DRCC is great in construction as you can just follow the flow of traffic (Assuming they're obeying the rules) and the car will resume speed when the car in front of you resumes speed. It's very convenient.

    Of course you need to always pay attention.


    Never had it auto-brake on bridge expansion joints but I have had the "BRAKE!" message show up if I'm approaching a fork in the bridge where two lanes go straight and two lanes bear to right and I'm on the second lane that bears right. It'll sometimes recognise the metallic \\\ sign (black/yellow) and beep. It'll has also beep (but even shorter than the above scenario) on expansion joints. The "worst" case was when it activated PCS-seatbelts but it was just once and it has never auto-braked.
     
  15. akhare

    akhare Member

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    Got to really try out the DRCC and really loved it. It's eerie to have the car do the slowing on the freeway etc. as needed and I had my foot right on top of the brake just in case, but it seemed to work very smoothly and accelerated with the traffic. Naturally one always has to be vigilant, but looks very promising so far.
     
  16. swich2mac

    swich2mac Go Hard or Go Home!

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    Until it fails? ;)
     
  17. David Beale

    David Beale Senior Member

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    Looks like the cruise control chip was changed or programmed differently from the 2010 to the 2012. Pearl S will not loose the set speed unless you actually turn off the cruise (cruise button to off or turn off the car). It retains the previous set speed even when stopped no matter how you stop. Once you get going above about 30 km/hr a quick up on the lever resumes the cruise at the previous set speed, with the radar tracking the vehicle in front.
    I've seen this before with Toyota cruise, one model looses the set speed and a different model doesn't.

    I don't "hover my foot over the brake" when I use the cruise. It works so well I trust it completely. Even when it gives up when slowing at around 30 km/hr, at that speed and the following distance it uses there is lots of time to stop manually. I usually use the middle following distance (there are three different ones you can select). If idiots want to cut in I let them. Better to have them in front of me so I can keep an eye on them. ;)
     
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  18. akhare

    akhare Member

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    Not sure whether there's intended sarcasm here, but blame Taleb's "The Black Swan" etc. for my distrust :p.
     
  19. 155

    155 Member

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    So after having driven with the new DRCC for several hours, there are two notes that I would say about it:

    1. Although it is full speed, it needs a vehicle in front of it to be moving to slow to a complete stop. If you are cruising up to a stop light and there is a vehicle stopped in front of you at that stop light when you get into radar range and you're going 40 mph, it seems that cruise control system will not slow the car and the collision warning/mitigation system will take over. If you are behind a moving vehicle that stops at the stop light, then your cruise control will take you to a complete stop behind that vehicle.

    2. If you are starting from zero at a stop light, and the car in front of you turns right, the cruise control system will deactivate and you will suddenly be thrust into normal driving mode. It feels like you suddenly got thrust into a pool. I'm not sure what the best way to handle such a situation is to get back into cruise control mode as quickly as possible.

    3. The cruise control system must be at above 28 mph for initial activation.

    Otherwise the cruise control system is great and works how you would expect it to although it leaves a huge gap when it stops behind a vehicle at a traffic light. It's amazing how well it keeps you at a constant speed all the time in traffic.
     
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  20. David Beale

    David Beale Senior Member

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    No sarcasm intended. Hovering the foot over the accelerator is not really a good idea, as I have found even slightly bumping it can cancel cruise.



    A quick up on the cruise lever will resume the cruise function at the previously set speed.

    Oh, and yes, if you are not paying attention the cruise will not save your rear end! YOU are driving/operating the car, so drive. Avoid stopped cars and idiots. ;)
     
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