Hi Folks-

Here's some interesting behavior and I'm wondering if anyone else has observed similar.

My GLS has the automatic speed limit control where the system sees/knows the speed limit and adjusts the speed automatically. The other day I was towing the new trailer I recently purchased. While towing, I passed a speed limit sign increasing the speed from 35 to 50. Interestingly, the little speed limit sign on the dash remained at 35, but the car sped up to 50. I assume that the trailer interfered with the camera vision and that as a result the displayed limit did not change, yet the car understood from the GPS database that the speed was supposed to increase, and the car reacted.

Do I have this right? Has anyone experienced similar behavior? It sure looks to me like there is some internal logic that tells the car what to do when it has both GPS and camera data, and then also in the other cases where it only has one or the other.

Does anyone understand how this all works?

Thanks for sharing.

 

I understand enough to never use it. It's tried to have me go 65mph down a side road. It's nowhere near accurate enough and is just another example of why self driving cars will never happen.

 

There's a 55mph zone near here and it drops suddenly to a 15mph in a school zone. My Audi recognizes that drastic change, and the school zone sign. and just flashes a yellow 15mph icon....but doesn't decrease the speed. My GLE, on the other hand, jams on the brakes... People behind me just love that, so I turned off that feature.

 

Yes, you're likely correct. The system seems to be using both GPS and camera data. When towing, the camera might have been obstructed by the trailer, preventing it from detecting the new speed limit sign, while the GPS database provided the correct speed limit information, causing the car to adjust its speed. The car seems to prioritize GPS data in this case, which explains the behavior you're seeing. This is a common feature in modern systems, where internal logic decides which data source to rely on depending on the situation.

 

We have more than one local road where the speed is 75 and the car thinks it is 55 or 65. One road in particular that is next to I75 (where the limit is 75) the car says it is 75 and it is really 30.....if you look at the map it makes sense....

 

I turn off my Speed Limit Adaptation because sometimes it sees something that isn't there, or doesn't see something that is there. Especially in the winter, when Sun angles are low.

I also don't use Route-based navigation for that reason and more.

 

As others have said, speed limit adaptation got turned off on our first road trip as it couldn't differentiate between the car speed limit and the heavy truck/bus speed limit among other errors like confusing a highway 80 sign for an 80mph limit.

 

That's the issue....... Mercedes offers OTA updates, but they're usually not very useful. In comparison, most BMWs I've owned since IDrive 7 (ID7) was introduced have received very useful OTA updates that improved the drive assist feature during my ownership period. Until today, 2019 ID7 cars are getting the same OTA updates that ID7 2025 cars are receiving (yes they still produce 1-2 models with ID7 today), and even for ID8, some of the OTA features related to drive assist improvements are also compatible and released at the same time to the older ID7. Since 2018/2019, they released 2-3 updates to improve lane change smoothness, improved accuracy of lane centering couple times, improved the HUD display information for navigation, and improved responsiveness during acceleration and deceleration with drive assist on. In the meantime, the only Mbenz update that i can see in the history of my GLS MBUX seems to be related to fixing bugs and making it easier to subscribe to traffic light warning services!!!! I love the brand but man I hate their tech so much! Way behind.

 

Maybe the BMW maladies that needed fixing were more obvious. Sounds like a bunch of camera problems.
I've had updates that only corrected sound imbalance, LTE ability, Connected Home improvements, Parking space reservation etc. Not as obvious, but average once a month. Plus map updates of course.