Unreliable Speed Limit Indicator

[steve933]

Do you guys find the speed limit indicator (on the dash or in the HUD) to be mostly unreliable? I have a '26 2500 AT4 and have noticed several times that it's wrong. For example, several times each week I go down a particular road where the posted speed is 45. When I pass the first speed limit sign, the display updates to 45 MPH just as it should. After a couple of miles, I make a left turn onto a residential street. Within the first 100 feet or so, the display updates to 25 MPH, but there was no sign for it to read. About 300 feet further (same road), it changes to 55 (no sign) until I pass the first speed limit sign on this particular road--it then correctly changes to 35 MPH. I thought that maybe the camera lens was partially obscured, so I cleaned all of them--no change.


I've seen several instances of incorrect speed displays--so many that I don't trust it anymore. My wife has a '24 BMW X7 with speed recognition and very rarely (if ever) have we ever noticed it being wrong--even on this same stretch of road.

Any idea what's going on?

 

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[Chopper_Man]

Has nothing to do with camera. It's GPS based which relies on published speed limits. It is the same for your wifes car, GPS based. Different GPS's, different databases. They are a "feature" and should not be relied on for your speed limit.

 

[steve933]

Thanks for your reply. Actually, the BMW uses a windshield camera as the primary input and map data as supplemental info--that's why I thought the GMC may be the same. Strange that any map data would this particular stretch as 55 MPH since it has always been 35 (residential).