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FSD and Autopilot adjust for yellow road signs

I have a MYLR Sept 2021 build with 2021.36.5 firmware. I have pue vision Autopilot, but not FSD.

When using Autopilot on a highway, it ignores yellow signs with recommended speed on curves and orange speed signs in construction zones. It does not slow down unless there is a white speed limit sign. I am quite surprised that setting Autopilot to use the speed limit does not adjust speed in these basic safety scenarios. It is quite alarming when it flies around a curve at full speed, rather than obeyed the slow down sign.

If I were to upgrade to FSD, would Autopilot adjust speed for tellow and orange signs or would I have to use Navigate on Autopilot to get the car to obey safety speed signs?
 

drtimhill

Active Member
Apr 25, 2019
2,913
3,765
Seattle
Neither NoA nor the new FSD beta (at present) take account of the yellow "advisory" speed limit signs, which is probably deliberate as if they did I think your car would be rear-ended in about 5 mins, given that no-one else pays them much attention. I presume that whoever set the rules for those signs drives a model T Ford.

Probably NoA/FSD should pay them some attention, but not as speed limits more as a warning that something upcoming may require a reduction in speed.
 
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RTPEV

Active Member
Mar 21, 2016
1,416
1,817
Durham, NC
Speaking of yellow advisory signs only (orange signs are a different matter), the car itself has knowledge of the topography of the road it is traveling upon and can (and does) adjust the speed accordiningly to navigate curves at safe speeds without the need for reading the yellow advisory signs.

That said the actual behavior of the car in these kinds of situations does tend to change over time as the software is updated.

As one particular example, there is a flyover interchange that I travel on frequently that has a long sweeping curve. The speed limit goes from 70mph on the exiting highway to 60mph on the entering highway (technically the 60mph speed limit does not go into effect until after this curve). There is a yellow advisory sign (40mph I think?) on the curve, but the actual speed of cars on this section is usually 60-70mph. Previously the car's cruise speed would automatically adjust down to 45mph on this curve (resulting in dramatic slowdown far below what other cars were doing). Believe me when I say this rendered autopilot in this section almost useless--I had to anticipate it and press the accelerator and manually adjust the set speed up every day! I'm almost certain the camera didn't read the advisory sign, but the map data might have indicated a type of road that caused the speed change. Eventually a software updated "fixed" this behavior and now the cruise speed only changes from whatever it was set to on the main highway down to 70mph on the off-ramp (I suspect I could alter this behavior in my settings) and then keeps it at 70mph until it enters the new highway. But how does it handle the curve? I will say that the car can certainly navigate the curve at 70mph, but it's a tad uncomfortable at that speed. 65mph is a more comfortable speed. The car does in fact slow down slightly around the curve, below the set 70mph, although not by much. But it is adjusting. On another nearby curve (without the set speed changes) it used to slow down for the curve, perhaps a bit too cautiously, but now it takes the corner at an almost uncomfortable speed. I suspect that this part of the software will be fine tuned and we will probably see a pendulum-like behavior until they eventually get it dialed in.

In summary, for yellow advisory signs I don't think it's necessary, or even desirable, for the car to actually read the signs, but it does need to consult the map as well as it's cameras to dynamically adjust the speed as necessary for safety and comfort.

As I said, orange signs are a bit of a different matter. I don't usually see speed advisories for construction areas--these days they are usually the traditional white signs with an orange top that says CONSTRUCTION ZONE, so far more of a requirement than an advisory, and the car certainly pays attention to these. Although in some places, these signs also have a blinking lights that indicate when the construction zone is active, and if the lights are not blinking, the speed limit does not apply. The car does not now how to interpret this, resulting in unnecessary slowdowns.
 

srs5694

Active Member
Jan 15, 2019
1,286
1,616
Woonsocket, RI
I've seen lots of people refer to Teslas "reading" speed-limit signs, but I'm not convinced it does so. I say this because I've seen my own Tesla report that the speed limit is something other than what the latest speed limit sign says it is, even right after passing a speed limit sign. This happens fairly consistently on one route I drive once or twice a month, which is a 4-lane undivided rural highway with speed limits that vary frequently. Based on my observations, I suspect that the Tesla is relying on speed limit information in its mapping data, not the posted speed limit signs. This information is available in Google's mapping data, so it seems sensible for Tesla to rely on it, if possible. I can't be 100% positive of this conclusion, though, and if there's something official from Tesla stating unambiguously that the car reads speed limit signs, then I'd be interested in seeing that. My car has paid-for FSD, but not (yet) the FSD-on-city-streets beta feature.

In any event, if I'm right, the Tesla wouldn't know a thing about construction-zone speed limits, since it's doubtful that the mapping data would include that information. I don't know offhand if the mapping data would include speed limit changes at highway interchanges and exits. There are some that my Tesla definitely tries to take too quickly when NoA is active; or at least, it tries to enter them too quickly. Maybe it'd brake hard much later than I would going into the interchange/exit. I've always braked manually at these points; I don't want to end up crashing through the barriers because of an Autopilot error.
 
I've seen lots of people refer to Teslas "reading" speed-limit signs, but I'm not convinced it does so.
It does read it from my experience. One example is driving on Indiana 45. The speed limit is 50 mph and the Hwy # sign is the same shape as the speed limit sign. My MYP would slow down to 45 passing the Hwy # marker and then speed back up passing the 50 mph speed limit sign.
 
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Tam

Well-Known Member
Nov 25, 2012
10,733
9,773
Visalia, CA
...If I were to upgrade to FSD, would Autopilot adjust speed for tellow and orange signs or would I have to use Navigate on Autopilot to get the car to obey safety speed signs?...

My feeling for paying more for FSD is about getting more features and not about improving what your current Autopilot performance is.

That means, if it has trouble with the curve that you mentioned, paying more for FSD would get you Smart Summons, Auto Park... but it does nothing about solving that particular curvy road challenge.

Autopilot/FSD does well with some curves and not others.
 

drtimhill

Active Member
Apr 25, 2019
2,913
3,765
Seattle
I've seen lots of people refer to Teslas "reading" speed-limit signs, but I'm not convinced it does so. I say this because I've seen my own Tesla report that the speed limit is something other than what the latest speed limit sign says it is, even right after passing a speed limit sign. This happens fairly consistently on one route I drive once or twice a month, which is a 4-lane undivided rural highway with speed limits that vary frequently. Based on my observations, I suspect that the Tesla is relying on speed limit information in its mapping data, not the posted speed limit signs. This information is available in Google's mapping data, so it seems sensible for Tesla to rely on it, if possible. I can't be 100% positive of this conclusion, though, and if there's something official from Tesla stating unambiguously that the car reads speed limit signs, then I'd be interested in seeing that. My car has paid-for FSD, but not (yet) the FSD-on-city-streets beta feature.
It does read speed limit signs (many others have tested this carefully), however its not perfect and it has been known to miss some (consistently). As you noted, the car also has access to speed limit in the map data, and uses this also. I'm not aware of how it resolves differences between the map data and posted signage (signage wins? lowest speed wins?).
 
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I'm not aware of how it resolves differences between the map data and posted signage (signage wins? lowest speed wins?).
Me neither, but I think the signs do take precedence in some cases. On several occasions my car didn’t adjust the displayed speed limit to reflect a speed limit increase because the speed limit sign was obscured.
 

RTPEV

Active Member
Mar 21, 2016
1,416
1,817
Durham, NC
It absolutely reads the speed limit signs. In my neighborhood apparently the street/map data does not have speed limit info, and the little SPEED LIMIT symbol in the display that shows the current speed limit is missing on the street--until I turn the corner and there is a 25mph speed limit sign. At the precise moment the sign appears on the visualization, the little SPEED LIMIT 25 sign appears on the display. Prior to receiving the s/w update that gave the car the ability to read the signs (or maybe it was my HW3 upgrade), this did not happen, so it's not just a coincidence that the map data suddenly indicates the 25mph zone.

As for the signs taking precedence, this too appears to be the case, with the scenario I described above. I have come across construction zone speed limit signs (the white kind with the orange tops that I mentioned above) and the car has slowed down and indicated the lower speed limit. The problem in these cases is that there is also a blinking light that indicates when the construction zone is active (and thus the speed limit applies). Unfortunately the car does not recognize/understand this and slows down even though the construction zone is not active and thus the speed limit does not apply.
 

drtimhill

Active Member
Apr 25, 2019
2,913
3,765
Seattle
As for the signs taking precedence, this too appears to be the case, with the scenario I described above. I have come across construction zone speed limit signs (the white kind with the orange tops that I mentioned above) and the car has slowed down and indicated the lower speed limit.
But that could equally be because the lower of the two possible speeds is "winning" (since the signage is lowering the limit in the map data). We would need to have a road where we know the map-based limit is LOWER than the posted signage limit to figure out how the car decides which limit wins.
 
I've seen lots of people refer to Teslas "reading" speed-limit signs, but I'm not convinced it does so.
I get the impression that the Tesla does read the signs. On a winding road in my neighborhood, the car seems unaware of the speed limit for the first half mile, until I pass a sign and then the speed limit indicator pops up.

On a recent drive from Arizona to California, when I entered California the car said that the speed limit was 55, because the first speed limit sign said that the speed limit is 55 for vehicles that are towing. The speed limit for other vehicles is 70 in that area, although we had not yet passed a sign indicating this. It took that car about 30 miles to figure out the correct speed limit. Every time I passed one of those speed limit signs for towing vehicles, the car reduced its indication of the speed limit. Meanwhile. Google Maps reported correctly that the speed limit on the California portion of Interstate 10 is lower than the Arizona portion. Fortunately, I set my speed on Autopilot manually, rather than relative to the speed limit, otherwise the car would have slowed down to be a good citizen.
 
Speaking of yellow advisory signs only (orange signs are a different matter), the car itself has knowledge of the topography of the road it is traveling upon and can (and does) adjust the speed accordiningly to navigate curves at safe speeds without the need for reading the yellow advisory signs.

I find that the speed that Autopilot takes on some freeway interchanges is excessive given the sharpness of the curve. That is why the advisory sign suggests slowing down to 45. The car maintains the speed that it drove on the previous freeway, which is pretty stressful, so I usually turn off AP until I get on the next freeway. The tires are not screeching, but the centrifugal force for the human occupants is pretty strong. I don't get any sense that that car slows down on curving freeway interchanges like a prudent human driver would. This is why I asked if NAP in FSD would do better with such situations. With regular AP, the speed seems to be locked in like vanilla cruise control, unless other cars ahead of it are slowing down.
 
Neither NoA nor the new FSD beta (at present) take account of the yellow "advisory" speed limit signs, which is probably deliberate as if they did I think your car would be rear-ended in about 5 mins, given that no-one else pays them much attention. I presume that whoever set the rules for those signs drives a model T Ford.

Probably NoA/FSD should pay them some attention, but not as speed limits more as a warning that something upcoming may require a reduction in speed.
While I would agree that we (all drivers, probably) take warning signs more as advisory notices, they should not be ignored. Here is an example that happened to me twice recently on abeta 10.8.1. I am approaching a stretch of curvy mountain roads. The speed limit is 45 mph. The warning sign suggests reducing speed to 35. FSD can 'handle' it, but it is quite twitchy on the steering and it speeds up and slows down like a drunk driver. it made my wife nauseated. If FSD were to do what the rest of us would do and maybe dial the speed down a bit and learn how to take the stretch of the road, then it would be smoother, and I would not have to disengage to save vomit in the car.

As for people rear-ending those who obey the rules, they are just plain wrong.
 

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