Speed Limit Detection Fails in School Zones.

[SpaceEVDriver]

School is spinning up again in the United States. I passed through an active school zone on my way to a meeting this morning. The AZ school zone sign looks similar to the one I've included here. In my area, the sign is usually mounted on a pole welded to an old vehicle rim or something similar and is rolled onto the center line of the 25 mph zone to make the zone a temporary 15 mph zone.

I don't know if anyone is foolish enough to use cruise control in a school zone, but the speed limit recognition algorithm does not react to this kind of sign. I suspect that's because the signs are only recognized when they're approximately 2-3 meters high and on the right-hand-side of the roadway, but could also be because the speed limit is only one small part of the text in the AZ signs.

I have automatic speed limit adjustment turned off and I don't use cruise control on non-highway roads, so this doesn't impact me, but I thought it was interesting that the algorithm has been poorly trained such that it doesn't see these very important speed limit signs.

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[Blue highway]

I can see where signs like this are a nightmare for the AI speed sign detection... it just doesn't look much like a traditional speed limit sign.

 

[SpaceEVDriver]

I can see where signs like this are a nightmare for the AI speed sign detection... it just doesn't look much like a traditional speed limit sign.

AI is easy to train for a priori knowledge--it's just pattern recognition using known data. It just needed to be fed the data. Ford (or whomever did the job) just didn't think about where school zone signs are likely to be (in the center of the roadway) or what they look like around the country.

 

[Blue highway]

AI is easy to train for a priori knowledge--it's just pattern recognition using known data. It just needed to be fed the data. Ford (or whomever did the job) just didn't think about where school zone signs are likely to be (in the center of the roadway) or what they look like around the country.

I dunno, I suspect that 99% of the speed limit data our cars use is from GPS sources... not the cameras. I say this because all my other cars show the speed limit but don't use cameras and it works (changes speed) in the Ford even where the speed signs have been stolen.

It looks to me as if AZ is one of the few or only places in the country that doesn't use the words "speed limit" on a speed limit sign. I've not thought a lot about it, but most places they look something like this:

not this

I can see one state easily being an oversight.

 

[rreddy3]

School is spinning up again in the United States. I passed through an active school zone on my way to a meeting this morning. The AZ school zone sign looks similar to the one I've included here. In my area, the sign is usually mounted on a pole welded to an old vehicle rim or something similar and is rolled onto the center line of the 25 mph zone to make the zone a temporary 15 mph zone.

I don't know if anyone is foolish enough to use cruise control in a school zone, but the speed limit recognition algorithm does not react to this kind of sign. I suspect that's because the signs are only recognized when they're approximately 2-3 meters high and on the right-hand-side of the roadway, but could also be because the speed limit is only one small part of the text in the AZ signs.

I have automatic speed limit adjustment turned off and I don't use cruise control on non-highway roads, so this doesn't impact me, but I thought it was interesting that the algorithm has been poorly trained such that it doesn't see these very important speed limit signs.

My MME recognizes speed limit sides to the left of the vehicle, not just to the right. I 66 in northern Virginia, in fairfax county outside the beltway and part of prince william county, has 4 main through lanes and two HOT lanes to fhe left if the main lanes each way. Speed limit sides are posted to the R of the HOT lanes and R of the main lanes. Main lanes are mostly 55, HOT lanes mostly 70. First time the car accelerated, quickly as you know they do, from 55 to 70 with traffic all over was a surprise! Although I’d like to see the car focus to the R, I know people have reported their cars picking up speed limit signs on exits or frontage roads to the R of the through lanes and decelerating. I don’t know what the engineering answer is. My remedy is to not use cruise in places I know the car will be confused and to pay attention to take control if needed.

 

[ECHARGD]

I have automatic speed limit adjustment turned off and I don't use cruise control on non-highway roads

Then how do you know the MME doesn't recognize the sign? Only way to know is to experience it. Have you??

 

[SpaceEVDriver]

Then how do you know the MME doesn't recognize the sign? Only way to know is to experience it. Have you??

Yes. The speed limit recognition is separate from the response to the speed adjustment based on speed limit.

 

[ECHARGD]

Ah, yes! I often overlook the speed limit indicator on the upper screen since it tends to be hidden behind the steering wheel. I also use Android Auto with Google Maps which posts the speed limit on the larger screen and tend to reference that more than the one on the right hand side of the upper display.

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