Cruise control speed drops unexpectedly

[JoeDimwit]

So what’s the difference from adaptive and intelligent? Will adaptive still slow down based on traffic? Is speed limit adjustment the only difference? If so I will turn that off.

Adaptive requires you to set your desired speed, then it attempts to go that speed until there is a vehicle in front of you. Then it will go the slower of (your set speed) or ( the maximum speed that allows a safe distance from the car in front of you).

Intelligent cruise is the same, except that it sets itself to the posted speed limit plus or minus and tolerance you have chosen to allow.

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[Deleted member 4669]

Adaptive requires you to set your desired speed, then it attempts to go that speed until there is a vehicle in front of you. Then it will go the slower of (your set speed) or ( the maximum speed that allows a safe distance from the car in front of you).

Intelligent cruise is the same, except that it sets itself to the posted speed limit plus or minus and tolerance you have chosen to allow.

adaptive it is then.

 

[RedStallion]

It absolutely reads signs. But, I think it still also will pull map speed limit data.

I've watched the speed limit change based on a temporary speed limit sign that 100% wouldn't be included in the map data. My Edge before the MME wouldn't do this, It only relied on the map speed limit data.

Have you compared it to google maps? So far I haven't seen a single instance where MME would read a speed sign that was different from the maps. Try putting a cloth with a different speed limit over a sign and see if MME would notice that.

 

[dml105]

It reads signs. We have variable speed zones in Virginia and it recognizes the current speed limit.

 

[Garbone]

There is a big of A1A in Flagler county that was 45 mph but after it was washed away in a hurricane it was rebuilt as a 25 mph zone. Intelligent cruise will ease you through until one spot then it rockets to 45. Not good in a 25mph zone on the beach.

 

[benk016]

Have you compared it to google maps? So far I haven't seen a single instance where MME would read a speed sign that was different from the maps. Try putting a cloth with a different speed limit over a sign and see if MME would notice that.

I have several examples where it is very obvious that is reading the signs.

Driving on interstate, go by an off ramp, speed limit sign on both sides of ramp, the car will occasionally think that is the speed limit for the highway and suddenly try to go from 75 to 45.

I've had a semi blocking the view of the speed limit sign. And so it kept displaying the lower limit until I passed the next sign that it could see.

The car also will use the map data for speed limits. If you turn on to a road and don't see a sign right away it will update with the speed from the map.

But the map data, in my opinion, should only be used if the car goes so long without seeing a sign or on a different road that you haven't come across a sign yet.

I have a spot near my house that the speed limit changes in the same spot every time and there's no signs at all. It's gotta be coming from the map.

 

[MailGuy]

Ok so it is related to the tolerance setting for intelligent cruise control. For some reason it was set to -13. I definitely did not do that so not sure how that happened but at least I have an explanation.

I will say after playing with it I dont like how it works. Let’s say i am on a one lane road and set it to 40 in a 35. Let’s also say I set the tolerance to +20. As I am driving and say the speed limit changes to 40 mph the car will change to 60 mph. I would expect the tolerance to be the max it will eat you set it to over the speed limit, not the default over the speed limit. Oh well now I know how to get it set up, thanks.

The car will use whatever you set until it reads a sign that varies from what was posted when you set it. It then applies the setting it reads from the sign plus your tolerance. Yes, it reads the sign because it works with variable speed zones, even when the speed limit is posted overhead in the lane you're driving in and the lanes have varying speed limits. I believe that tolerance is meant to be used as an incremental change. I have my tolerance set to +2 to account for variation in various OEM speedometers and it works well and smoothly. If I want to override my default tolerance and do +5 I simply set that and the system keeps at speed limit +5 for as long as the legal speed limit I'm driving on doesn't change. Once it sees a sign that is different from the speed limit that I've been driving in, it matches the new legal speed limit it read and applies the tolerance I have configured. Setting a tolerance that is 50% (or even 33%) of the speed limit, your experience is likely going to vary.

 

[ChasingCoral]

It seems to be random and not related to the speed limit. I also believe I turned off the setting for match or adjust to speed limit, though I could be wrong on that.

If you turned off the speed limit setting you are in Adaptive Cruise Control, not Intelligent Cruise Control. The difference between the two is the automatic (optical) speed setting.

 

[ChasingCoral]

It reads signs. We have variable speed zones in Virginia and it recognizes the current speed limit.

Sometimes it reads signs that aren't speed limits, recognizing a speed limit number where none exists. I once had mine suddenly reset from 65 to 84 when I passed a SR-84 sign.

 

[ChasingCoral]

Is anyone else having issues with the cruise control feature? I have been trying the intelligent cruise feature and have notice almost all the time i use it a minute or 2 max after I set the speed it will drop to a much lower speed. For example I set it to 50 mph, 45 seconds later the car slows down and it says its set to 22 mph. This type of thing keeps happening. Is this a known issue? I couldnt find any threads. I am not encountering any obstacles or vehicles it literally just slows down.

The important thing to note when this happens is what the car thinks the speed limit is. What does the sign on the right side of the instrument display think the speed limit is currently?

 

[Mirak]

I tried Intelligent ACC for a few months but I recently switched back to regular ACC. The “Intelligent” ACC just isn’t smart enough for my driving. More than half of my driving is my work commute, and much of that is along a highway with frontage roads. The system keeps getting fooled by the frontage speed limit signs and it is very annoying having the car suddenly drop from 65 to 40.

Sign-reading CC is a fun idea but it doesn’t work well enough yet. I’d prefer to just set my cruise and go.

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