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BarrieHart

Prius+ Cruise Control

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Can anyone explain to me why my Prius+ adaptive cruise control trips out at 25mph? Adaptive CC would be incredibly useful when crawling in heavy traffic under 25mph (a la Nissan Leaf!).

Also when attempting to use CC to hold the car back on a steep incline at, say, 30mph it gradually accelerates past 30mph?

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Adaptive cc does not work below a certain speed - 25mph sounds about right.

Going down steep incline is exactly what B mode on the gear selector is for.  Never even thought of using cc going down a steep hill.

Is this car new to you? You can pick up loads of tips on You Tube

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That’s how the car works, no cruise control under certain speeds and in your car seems like it’s 25 mph, but yes if you set the speed at 30mph the car will keep it 30 at least my Toyotas does it. 
Regards 

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Cruise control doesn't work when going downhill.

It cuts out the drive down a hill, but gravity takes control and the speed increases.  Try it down a long 10% hill for instance.  Fine on a motorway or a major road, but in a 30mph limit with "contours", it's useless. 

Mick.

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More recent versions of CC will put the brakes on going downhill.  The latest Safety Sense 2 Adaptive Cruise Control on my RAV4 can be set to hold a speed down to 18 mph, but of course will follow a car down to 0 mph.

Unlike earlier versions, 'Resume' can be used right down to 0 mph, so that when stopped at traffic lights, it will hold the hydraulic brakes on (with brake lights) and start accelerating (keeping a safe distance from a car in front if there is one) once 'Resume' or the accelerator is pressed when any vehicle in front starts moving - if there's no vehicle in front, it just starts accelerating up to the set speed.

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9 hours ago, PeteB said:

More recent versions of CC will put the brakes on going downhill.  The latest Safety Sense 2 Adaptive Cruise Control .................

This is a very different beast to bog standard CC.  Excellent system though. 😀

Mick.

 

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Mine holds the set speed down hills, it applies the brakes, and it works down to 0 mph providing there is traffic in front, that's why it's called "adaptive" cruise.

You can't set it below 25 mph and it won't work below 25 mph if there are no leading vehicles in front but it will kick out as soon as you touch the brakes. 

It's a bit like a game of chicken when you're going at speed and approaching standing traffic, it comes to a stop quite sharply and way later than is comfortable for me, although I have learned to trust it. Whatever you do don't touch the brakes then release them in this situation as the cruise is no longer on. 😨

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I'm digressing onto my moans about cruise control.

Is "adaptive cruise control" actually cruise control in the accepted sense?   Time has moved on, and the old fashioned stuff has been superseded.  I'm getting too old! 😀

https://en.wikipedia.org/wiki/Cruise_control

Mick.

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I would say yes.

When you select a set speed and activate ACC it holds that speed just like ordinary CC.  Where it differs is that when the radar (and possibly camera) detect a slower vehicle in front, it slows down to keep a safe distance, braking if required and coming to a complete stop if the vehicle in front stops.  If the car in front accelerates or gets out of the way, or you change lanes to a clear one, the ACC will accelerate again until it reached the set speed.  If ACC has brought you to a stop, it may require prompting to set off again after the vehicle in front moves (usually by briefly dabbing the accelerator or pressing the resume control) and accelerates as before up to the set speed or to keep a safe gap.

On Toyotas and Lexus cars with ACC (and probably other makes) you can choose to use ordinary CC by pressing and holding the master CC button when you switch it on.

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ACC main difference for me, is that it keeps the set speed down hills!

Coming down Gunnislake Hill A390 into the village yesterday on my bike, I was doing 42mph freewheeling.  It's a 30mph limit for motor vehicles.  12% hill.

https://www.google.co.uk/maps/@50.5156805,-4.224098,3a,37.5y,71.69h,78.94t/data=!3m6!1e1!3m4!1sqX-CDlrXYMJGgIoHEXtaLA!2e0!7i13312!8i6656

The car in front was going faster than me, and the cars generally do 40odd mph down the hill into the village.  Going up, most do maybe 50mph.  Yes, the police should do something, but unless there's an accident, nothing will happen.

Sorry, I digress yet again .................

If I set CC on our Yaris Hybrid up where the 30mph limit starts, all is fine and dandy.  Trouble is, when I hit the hill towards the village, the speed rapidly increases and CC becomes pointless.  All it does is shut off the drive, and gravity takes over of course.

Mick.

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PS:

If you fancy a ride down the hill, check out my Youtube movie.

 

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Whoa!  Raleigh Chopper - you mean the one with the large rear/small front wheel and shifter like an auto car?  Can't remember the last time I saw one, weren't they from the 1960s/70s?

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7 hours ago, PeteB said:

Whoa!  Raleigh Chopper - you mean the one with the large rear/small front wheel and shifter like an auto car?  Can't remember the last time I saw one, weren't they from the 1960s/70s?

Perhaps he meant Raleigh Shopper, you know, the bike older ladies ride with a shopping basket on the handlebars 😁

Thats some seriously long hill. I wouldn’t like to be going down that on a bike with dodgy brakes (not suggesting you were)

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11 hours ago, PeteB said:

Whoa!  Raleigh Chopper - you mean the one with the large rear/small front wheel and shifter like an auto car?  Can't remember the last time I saw one, weren't they from the 1960s/70s?

The scourge of A&E the length and breadth of Britain in the seventies.

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15 hours ago, PeteB said:

Whoa!  Raleigh Chopper - you mean the one with the large rear/small front wheel and shifter like an auto car?  Can't remember the last time I saw one, weren't they from the 1960s/70s?

Ah, the nutcracker shifter. 😄

 

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It seems that Barrie, the original poster, last visited at 10:40pm last Thursday, a few hours after posting. This means he probably saw the first 3 replies. Why do people join, ask a question, then disappear.

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4 hours ago, Catlover said:

It seems that Barrie, the original poster, last visited at 10:40pm last Thursday, a few hours after posting. This means he probably saw the first 3 replies. Why do people join, ask a question, then disappear.

'twas ever thus on forums ........... or is it fora?

I've been on a few over the years, and a long-time member of cycling uk forum.  I was a member of it before the present incarnation of the forum, and the one before that and the one before that too.

https://forum.cyclinguk.org
Over 46,00 posts in the present forum from 2007, but I joined in 2004, so it could be 60,000 or more.  Grief! It makes you think! 😮

Mick.

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On 10/5/2019 at 2:05 PM, Catlover said:

It seems that Barrie, the original poster, last visited at 10:40pm last Thursday, a few hours after posting. This means he probably saw the first 3 replies. Why do people join, ask a question, then disappear.

Could be a friendly Troll, not argumentative like the normal ones. 🙄 

 

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I haven't disappeared - I'm here! Thanks to everyone for your replies but no-one has really explained WHY!

Need to change the car next April so will see if Toyota come up with 'sensible' adaptive cruise control as some of describe - otherwise it's over to the Nissan shop!

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Where are you likely to be doing 25mph or under?  More then likely built up areas? In built up areas it is more likely unexpected circumstances will occur requiring the driver to act quickly ie pedestrians walking into the road, cars making unexpected movements, traffic lights changing to red etc.  All of these need driver attention and possible reaction. iMO activated cruise control in such situations is not conducive to safe driving . Where is your right foot when using control? More then likely resting somewhere away from the accelerator pedal. Imagine driving along at say 25mph, ccontrol engaged, right foot relaxed. Situation arises requiring you to brake. If your foot was on the accelerator (ccontrol  or activated) then just taking your foot off to put on foot brakes would start to !Removed! the car, quick application of the foot braked would apply brakes. Not so with ccontrol engaged. So, I consider it unsafe to use control in built up areas when under 30 mph for the stated reason. Whether or not that is Toyotas reason in your Prius i don’t know.

 

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On 10/3/2019 at 5:28 PM, BarrieHart said:

Can anyone explain to me why my Prius+ adaptive cruise control trips out at 25mph? Adaptive CC would be incredibly useful when crawling in heavy traffic under 25mph (a la Nissan Leaf!).

Also when attempting to use CC to hold the car back on a steep incline at, say, 30mph it gradually accelerates past 30mph?

I can't explain why your Prius+ doesn't do both, but as Kitmo said for his, the 2016 'ordinary' Prius I had until recently did hold speed when following traffic down to zero mph, regardless of what set speed was selected, and it did put the brakes on going downhill.  If your car has the first Safety Sense package, I would have expected it to be the same.

Every car I've driven with ACC has behaved this way, including some Lexus Hybrids 10-11 years ago.

The minimum set speed on the 2016 Prius ACC was 28 mph, whereas my 2019 RAV4 (which has version 2 of the Safety Sense package) can be set down to 18 mph, which makes it really useful in long, straight 20 mph zones, and means I can spend more time looking out the windows and less looking at the speedo (especially as the RAV4 doesn't have HUD!).

Personally, I think, used correctly, the ACC coupled with an attentive driver makes perfect sense in slow moving traffic on dual carriageways and motorways, or even single carriageways where there's a slow or stop/start queue.  The ACC is very reliable and on a longer journey this can mean less fatigue for the driver.  I do keep my foot hovering over the brake pedal when there are pedestrians, cyclists or animals around the car, so I should be on it faster than if I have to come off the accelerator first.  Obviously, the driver needs to be alert as to when it is safer to cancel the ACC and go native.

I would hope in many situations the Autonomous Emergency Braking system would cut in even faster than I could, but I regard this as a backup rather than my primary line of defence.

 

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16 hours ago, Catlover said:

Where are you likely to be doing 25mph or under?  More then likely built up areas? In built up areas it is more likely unexpected circumstances will occur requiring the driver to act quickly ie pedestrians walking into the road, cars making unexpected movements, traffic lights changing to red etc.  All of these need driver attention and possible reaction. iMO activated cruise control in such situations is not conducive to safe driving . Where is your right foot when using control? More then likely resting somewhere away from the accelerator pedal. Imagine driving along at say 25mph, ccontrol engaged, right foot relaxed. Situation arises requiring you to brake. If your foot was on the accelerator (ccontrol  or activated) then just taking your foot off to put on foot brakes would start to !Removed! the car, quick application of the foot braked would apply brakes. Not so with ccontrol engaged. So, I consider it unsafe to use control in built up areas when under 30 mph for the stated reason. Whether or not that is Toyotas reason in your Prius i don’t know.

 

In the situations you describe, only one of those would require driver involvement, that's when the traffic lights change to red. The ACC obviously doesn't read traffic lights, it just works off the vehicle in front. But in the other situations, the car's PCS with TSS would react. The car has pedestrian (or object) detection, so if a pedestrian walks out, or a car turns in front of you, the car will tell you to brake or if the said pedestrian or car is close to collision it will brake. Have faith Joe, use the force. :ninja:😄

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We have both the Prius PHV and a Skoda Octavia with Adaptive Cruise Control. Both have proved to be reliable and a real boon to both cruising and in-traffic situations. The Toyota system is slightly better in that when a full stop happens it applies the brakes and resumes by simply pressing the accelerator. The Skoda comes to a full stop and then advises the driver to apply brakes, requiring operation of the resume switch. Both systems retain the last speed setting after being disengaged (usually by me braking into a bend) so resume quickly restores the set speed if safe by flicking the resume switch. In slow moving traffic they both maintain distance and slow to a full stop.

I have not noticed a problem starting the ACC at any speed, but both have minimum cc speeds about 25mph. As mentioned earlier the Toyota has a tendency to disengage at slow speeds if the leading car turns off - disconcerting at times.

I cannot see me choosing any future cars without ACC. (anymore than I would choose a car without air con/climate control or a Dab radio).

 

Cheers

Tony B

 

 

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18 hours ago, toshtosh said:

...I have not noticed a problem starting the ACC at any speed, but both have minimum cc speeds about 25mph. As mentioned earlier the Toyota has a tendency to disengage at slow speeds if the leading car turns off - disconcerting at times...

The latest incarnation (on cars with Safety Sense Version 2 it seems) can have a 'set speed' down to 18 mph (very useful in 20 zones) and resume now works down to 0 mph.  Yes, you can even select resume while stationary.

It doesn't seem to disengage when cars turn off so readily, the only disconcerting thing until you get used to it is when a car in front turns to an exit and slows down, the ACC will briefly assume you're following an brake accordingly - which can also take the car behind you by surprise if you don't deal with it.  Tapping the accelerator briefly cures this.

 

18 hours ago, toshtosh said:

...I cannot see me choosing any future cars without ACC. (anymore than I would choose a car without air con/climate control or a Dab radio)...

I'm with you on the first two, can take or leave DAB, but that's a personal thing.  I actually upgraded a perfectly good Gen 3 Prius to the Gen 4 partly to get the ACC, but also the other modern safety systems.

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