When visual speed sign detection was first rolled out
[UK] 2020.36.x the release notes stated that it was for 'local roads'. As there is no useful definition of what a 'local road' actually was, and having local roads where visual signs were not being detected
[UK] 2020.36.x I was quite mindful of trying to find what was and was not a, by the definition of the release notes, a 'local road'.
Temporary road works signs have always been detected right from day 1 in UK.
[UK] 2020.36.x and
[UK] 2020.36.x
As an FSD owner with NoA (navigate on autopilot), initially what became the common factor as to whether a stretch of road the signs were detected and visualised seemed to be aligned with whether NoA was available. If NoA was available, then that segment did not have visual speed sign recognition. If NoA was not available, speed signs were visually recognised. Whether the car honoured the speed limit was another matter entirely
Car adjusting speed for Speed Limits ? which, like speed sign recognition, has seemed to functionally have changed slightly over time.
What now appears to have changed slightly is the definition of 'local road'. What I have noticed over the last few months or more is that some segments that are NoA enabled now also have speed signs that are visualised, including a set in one of my posts linked above, on an dual carriageway A road (A331 at Farnborough). In this particular case, the car is still blind to speed signs in some sections of the road. Another earlier post of mine mentioned a road sign on the M3 now being recognised when previously it was not. However, what is common to both these signs is that they are in reduced speed limit sections. The A331 signs in the 50mph section are now showing, but not those is the NSL section, yet both are NoA enabled segments. Similar is true of the M3 sign. It is in a 50mph intersection merge zone.
Whether this following empirical insight has any bearing on reality I do not know, unfortunately dates when behaviour changed is a little hazy, but on both (so not a great sample size) these instances, the speed limits on both those sections of road were changed over the past few years and only reflected in the last nav map update. As we know that the car does still uses the underlying GPS/map based speed limits as a fallback (such as when a speed sign is incorrectly recognised from a side road at a junction which is then quickly reverted to GPS/map based limit after passing the junction but before a visually recognised sign is reached
New Navigation Maps for Europe Rolling Out 2021.8 /
another post and
and another) I wonder if ironically it is using GPS/map based hints as a trigger for whether it uses visual speed sign detection or not. Possibly it is that functionality that has changed, either in software or in map data?
