Speed Limit confused by route signs... Huh!?!?

sesullivan

New member
Apr 15, 2024
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Am I the only one seeing this rather glaring "oopsie" with FSD 12.3.4? Whether FSD is in use or not my MYLR gets confused about the speed limit. This came up when driving on US Route 20. It seems to take the route marker signs as a speed limit resulting in an abrupt slowdown (with FSD engaged) and a wrong speed limit indication on the screen when not. I expect there would be similar issues with US Route 10, 15, 20, 25, 30, 35, 40, 45 and so forth.

When this happened the first time I got slowed to 20mph from 50 and a well deserved honking at! Now that I know the expect it I drop out and leave a comment or use the left scroll to override.
 

sesullivan

New member
Apr 15, 2024
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Near me I have US Route 20, MA Route 30 and MA Route 60 and MA Route 70. I rarely drive the last 2 but have seen the issue on US Route 20 (original post) and MA Route 30.
This issue can are one respondent pointed out cause of deserved honking and with an inattentive driver following the potential of getting rear-ended. :-(.
As of FSD 12.3.4 It seems less sensitive to mistaking the US Route 20 signs though it has done it at least once. MA Route 30 is still regularly mistaken.

Here is an example of a a US Route Marker and a state route marker:

1713974608908.png1713974373434.png
 

PrescottAZRichard

Active member
Oct 28, 2022
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I can see that happening. While I haven't had that in AZ (good thing it doesn't when I'm driving on HWY 169) I have had it miss some SL signs. 12.3.4 is picking up school zone SL signs for me, but once through the crosswalk the speed doesn't return to the posted for that street. Just report it with an audio note whenever possible I guess. That's what I do. My guess is Tesla has to teach FSD what each state's route signs look like. I can see where that's annoying!
 

EdinEPTX

New member
Apr 21, 2024
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Near me I have US Route 20, MA Route 30 and MA Route 60 and MA Route 70. I rarely drive the last 2 but have seen the issue on US Route 20 (original post) and MA Route 30.
This issue can are one respondent pointed out cause of deserved honking and with an inattentive driver following the potential of getting rear-ended. :-(.
As of FSD 12.3.4 It seems less sensitive to mistaking the US Route 20 signs though it has done it at least once. MA Route 30 is still regularly mistaken.

Here is an example of a a US Route Marker and a state route marke

View attachment 221View attachment 220
If you put the word TEXAS on the 30 sign (above or below it) you'd have the Texas state route sign..
 

Las Lion

New member
Apr 6, 2024
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ok. This is my main concern lately. I think it started with a software upgrade. I have Auto Pilot, when I start on a highway it starts at 45, 55, 65 or 75. But when I enter a slow down area. Like small town, a big curve or an unmarked road, my car drops down to the lower speed and stays there for miles or until I take it out of Auto Pilot. Or just use Cruse for the rest of the trip. Today I found a way to fix it. I travel the same route daily. Its "not" marked but my car says 45 so I set it 5 over to 50. I go into a slow area it shows 35 but never would return to 45. This time I just turned off the main road onto a side road. Then re-enter the main road. Now it's back to 45. This works for all ares and all speeds. (just get off and return) A fix would be let me set the Auto Pilot speed just like Cruise control. And why is it only 5 over anyway? Everyone pass me at 60
 

djalan2000

New member
Apr 25, 2024
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There is a road here in Ventura County that has a speed limit of 50 to 55 mph. However, it only has signs you can see while driving 'Northbound'. The road has NO speed limit signs for MILES on the other side so FSD wants to limit the speed to the only thing it knows for the road - 45 mph, which ticks off a lot of drivers behind me. I wish there was some way to tell the system or maps or such that the speed goes up to 50 and then to 55 just like the other side does (although the other side has 55 and then 50 and then down to 45). It's kind of annoying to have it drive slow when it's not needed. Oh, and it's a one lane road (each side) with double yellow lines so no passing.
 

Las Lion

New member
Apr 6, 2024
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ok so we have a big problem with this. Can anyone find out if Tesla is working on this or even knows? Or maybe we can all do something together. I even told the Tech at my last service call. He said ya everyone knows but the %$# problem but nothing I can do...