Erroneous Speed Limit Posting

[FirstFord]

I know that other vehicle make/models have the speed limit posting feature, but this is my first vehicle that has had it, and I must say that I really like it. I will also confess that I have no idea how it works. Unfortunately, I am starting to get erroneous / incorrect speed limit postings.

I live in an area where there is only one way in, and one way out, on a 2-lane blacktop state highway. The speed limit is 55, and has been practically forever... The truck speed limit posting used to always be correct - but not anymore. It reads correctly (55 MPH) heading one direction, but coming back from the other direction, it will read correctly for awhile, and then drop to 25 MPH, when I still have miles of 55 MPH left to go (NO - the speed limit did NOT change!). The location where it drops incorrectly from 55 to 25 is inconsistent. One time I tried to fool it, and after it incorrectly dropped to 25: I turned off the two lane blacktop and went down a side road for 20 or 30 feet, turned around, and re-entered the original two lane blacktop highway. It now read 55 correctly! But only for a few thousand feet, and then it went back to incorrectly posting 25. It seems to only be happening on this one highway, but I will also admit that I don't watch the posting every second while I'm driving, so in my mind it is at least conceivable that it is happening elsewhere.

Since I don't know how these systems work, I don't know where to even start. And the kick in the head is, I'm pretty confident that it will be completely fruitless to take it to my dealer, because all I will get back is a "Cannot replicate" statement. Any ideas?

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[Viper]

My 22 Limited PB does something very similar, Comming out of my APT complex, speedo says 35 Mph in both directions but speed signs in both directions say 40. Always does this in the same places on this road. odd...

 

[My 2ND Ford]

I know that other vehicle make/models have the speed limit posting feature, but this is my first vehicle that has had it, and I must say that I really like it. I will also confess that I have no idea how it works. Unfortunately, I am starting to get erroneous / incorrect speed limit postings.

I live in an area where there is only one way in, and one way out, on a 2-lane blacktop state highway. The speed limit is 55, and has been practically forever... The truck speed limit posting used to always be correct - but not anymore. It reads correctly (55 MPH) heading one direction, but coming back from the other direction, it will read correctly for awhile, and then drop to 25 MPH, when I still have miles of 55 MPH left to go (NO - the speed limit did NOT change!). The location where it drops incorrectly from 55 to 25 is inconsistent. One time I tried to fool it, and after it incorrectly dropped to 25: I turned off the two lane blacktop and went down a side road for 20 or 30 feet, turned around, and re-entered the original two lane blacktop highway. It now read 55 correctly! But only for a few thousand feet, and then it went back to incorrectly posting 25. It seems to only be happening on this one highway, but I will also admit that I don't watch the posting every second while I'm driving, so in my mind it is at least conceivable that it is happening elsewhere.

Since I don't know how these systems work, I don't know where to even start. And the kick in the head is, I'm pretty confident that it will be completely fruitless to take it to my dealer, because all I will get back is a "Cannot replicate" statement. Any ideas?

The truck sees a speed limit sign and that is what changes the icon in your display. The icon will remain the same until the truck sees a different speed limit sign. It may be seeing a sign that is off of your road , but still visible to the camera. Unless something else is going on with your speed limit sign recognition software this is probably the case.

 

[powerboatr]

truck also uses google to set speed limits and construction zones
in my area we have 70 mph 2 lane
but exactly at the road work sign that drops it to 60 it drops to 60 on the speedo, has for months
its not the truck, its the information fed to it.
yes it can read signs...but thats not all if you use the built in nav
plus google is notorious for being WRONG

our other 2 lane is 65 by txdot signs
yet google routinely switches from 70 to 65 about every three weeks
and...if you use AA it also will display what google has listed.
i am not sure what takes precedent? trucks eye ball or google or mapquest

 

[Rjschatts]

Mine does that also, Apple Maps I found to be inaccurate also. Mostly correct on the highway but the rural roads it’s hit and miss.

 

[Antimatter22]

My truck does this on a back country road on my way to work. 55mph and no speed limit signs or any other street signs anywhere close and it will drop to 25mph. It's not ideal when the truck hits the breaks hard for no reason and someone is behind you. I normally just cancel cruise control when I get in that area.

 

[TJE]

Mine also does this on my way home from work. 40mph zone, but there are a couple of highway signs that seem to make it think the speed limit is 70mph, but only if I'm in the far right lane (2 lane road each direction).

 

[Mosey]

Don’t trust anything you read (or get) on the internet.

 

[FirstFord]

Wow! That's both interesting and disappointing, all at the same time. The good news is that apparently there is nothing wrong with my truck. The bad news is that it is sounding like there is nothing that I can do about it. That's a shame, because I really liked that little feature, and it has helped me out a few times. Now it looks like I will not be able to depend on it.

Thanks for the input from all.

 

[Kanuck]

It has to use GPS and google maps. My truck will drop the speed sign when I take the turn off at an overpass and the speed sign will show up when I enter the highway again.

 

[parkerdog]

Mine used to drop the cruise to 45 on a two lane state highway for no reason then I noticed the other day that it had quit doing it. No rhyme or reason. I had some neighbors down the road that had a kid start going to school and the state installed watch for stopped school bus, I always wondered if that showed up in navigation some way and caused it.

 

[HammaMan]

The phantom speed limit change is part of ford's navigation that's populated with data from here.com. People have said they made changes that appeared in as little as 4 months with some data changes they made never appearing. I made considerable edits to my town, not sure if they've shown up. One of the roads that's a 55mph zone has a phantom 30mph trip in it that triggers both my truck which is assist 2.0 system and my mach-e that's full active blue cruise. The road was claimed to have "highly accurate mapping" of that area which is complete bullshit as in the 10 years I've been here there's never been a 30 mph zone on it as it's a state highway. You can't change any details of their lidar mapped roads, of which that's one.

That same road is one of the very few locations GM's supercruise (blue cruise) actually worked. Unlike ford, GM's supercruise is either completely hands free or only radar cruise with no lane centering.

 

[cheesedogf150]

While highway driving trucks sometimes picks up the parallel off ramp speed. It’s very dangerous and could lead to an accident as the adaptive cruise hits the brakes pretty hard.

 

[powerboatr]

Wow! That's both interesting and disappointing, all at the same time. The good news is that apparently there is nothing wrong with my truck. The bad news is that it is sounding like there is nothing that I can do about it. That's a shame, because I really liked that little feature, and it has helped me out a few times. Now it looks like I will not be able to depend on it.

Thanks for the input from all.

i turned off the speed sign recognition part that makes truck try to run the speed it see or detects
it scared the crap out of me on 2nd day
i was in a 35 school zone and as soon as i passed the zone, it jumped back to 70...truck took off like a shot and i about crapped my pants
now i just have the speed limit indicated on the speedo

 

[HammaMan]

i turned off the speed sign recognition part that makes truck try to run the speed it see or detects
it scared the crap out of me on 2nd day
i was in a 35 school zone and as soon as i passed the zone, it jumped back to 70...truck took off like a shot and i about crapped my pants
now i just have the speed limit indicated on the speedo

Yeah, I have to manually take over in school zones. It's far more useful than hinderance though. We're a +10 state (by state law) so mine is set at +10. On unfamiliar roads I'm more than happy to let it handle the speed. It's particularly useful in the MME as it can really creep up in speed if you're not paying attention. With an EV you have no engine sound so you can't tell it's increasing in speed unless you're watching the speedo which I never do. I just let the vehicle handle it.

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