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Speed Limit Warning question on Autosteer

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I had the Speed Limit Warning turned ON during the Navigate on Autosteer. The instrument panel displayed the current speed limit (70) as determined by the highway sign; then after a few minutes, the speed limit decreased to 55 MPH on the same highway and the new speed limited showed on the dashboard; however, my MX did not change the speed limit accordingly. This similar scenario happened in several areas, but didn't update the speed on my MX. Anyone know the reason(s) or why the auto speed didn't kick-in automatically? Thanks!
 
It isn't supposed to change set speeds based on speed limits, and IMO, it shouldn't. Not too long ago, they started changing the set speed to your current speed whenever you disengage AP using the steering wheel, and they thankfully since reverted that change (I suspect it was a bug when it happened in spite of some people thinking it was a good thing). Outside of that scenario, up until recently, it would only change the set speed on surface roads where it was limiting the speed to 5 over the (often wrong) navigation-data-stored limit. More recently, it started to sometimes adjust the set speed at on/off ramps in addition to that (in different ways in different locations), but if you are actually using Navigate on AP, you are NOT on a surface road and your max speed setting won't be getting changed unless it is only briefly for a ramp (but anywhere I have experienced an on/off ramp that would change my set speed, it would also turn Navigate on AP back off because I was going to a surface road). As far as I'm concerned, Tesla (or mobileye) made a mistake when they decided to change the set speed for surface roads based on the speed limit, and they've only exacerbated that mistake by doing it more often (clearly causing users who are supposed to be driving to think otherwise). Instead, if they need to limit the speed for beta/safety reasons, they should have had a separate pop-up indicating AP is being limited to a certain speed while still showing your higher set speed, because you set it (that is to say this: IMO, until we have FSD and the car is setting the speed to begin with, it shouldn't be adjusting it).
 
Keep in mind that it does NOT read the speed limit signs. It uses your GPS position and refers to its own internal database about the speed limit at that GPS position - it is often wrong. It has to be very difficult for Tesla to create a speed limit database that is actually correct everywhere since speed limits change and it is an enormous amount of data to compile. So when my X is wrong about the speed limit, I cut it some slack and manually change it myself. Technology is improving, but we still need to be vigilant about verifying everything when using Auto Pilot.