Navigate on Autopilot/TACC drops MAX speed without any obvious reasons

[AndrasCsanyi]

I have a Model Y Performance with the latest and greatest software updates. Navigate on Autopilot and all the magic there is enabled except Traffic Lights section.
Recently I experienced that when I drive 100km/h around Amsterdam using the Ring (where we have a lot of merges and forks, but only half ot the times with speed limit lower than 100km/h) the MAX 100km/h drops to 97 km/h or 88km/h and the car starts to deccelerate. Today in one occasion it dropped to 40 km/h from 100km/h with medium traffic. In the latter case probably the navigation and map data is the one to blame for. The section I drove through is a construction and many roads are crossing and as the car started to slow down the navigation changed and wanted me to turn. The other addition to this is that Google Maps navigation data from the Netherlands is faulty. I had many cases where it was just plain wrong.
In these cases Autosteer is not enabled, only TACC.
Have you seen this behavior? Do you have an idea why it happens? Is there any chance the lower quality navigation data messes up the situation?

TRaffic Lights is disabled because in the Netherlands highways have special lights to enable/disable lanes and control trafic speed and many times Autopilot recognises these as Traffic Lights only for 1-2 seconds, but it is enough to jerk one on the car. PRetty much an unpleasant experience.

I also experience with TACC and Autosteer enabled that when there is a speed limit sign the car randomly lowers the speed to the speed limit. For example, I drive with 80km/h and there is a 60 speed limit the car continues with 80km/h (MAX 80) the maps shows 60. This scenario is the most common. But quarter of the time it lowers the speed to the speed limit sign. For example, I drive with 80km/h and there is a 60km/h the MAX will be lowered to 60 and the car slows down.
Why does this adjust to the speed limit in this hectic way?

I also experienced that TACC with Autosteer occasionally does not let me to set up higher speed than what the map shows. For example, I drive with 60km/h where the speed limit is 60km/h but I want to go fast with TACC and Autosteer enabled so I scroll upwards, but the MAX value does not change.
Why does it do this?

A few times I probably also see that when I enable TACC below the speed limit and I start scroll upwards to setup the speed, the MAX value does not go by 5, but rather jumps to the speed limit. For example, I go up to a highway (which is 100km/h) with 70km/h and I enable TACC at MAX72km/h and I start scrolling up the speed it jumps to 100 instead uf stepping up the speed by 5km/h.

I'm really satisfied with the TACC and Autosteer, but these anomalies or random things are driving me crazy. Especially that speed decrease from 100 to 40 on the middle of the highway.

 

[AndrasCsanyi]

A few days ago I drove the same route where the from 100 km/h to 40 km/h drop happened, and it happened again. I believe it is due to bad map data. They are building a bridge and the car reads the navigation data of the road below the bridge.

 

[bumcurriculum]

I experience the same with a Model S 2018 EAP AP2.5 which was imported from the Netherlands to Hungary.

It is also choosing the speed very sporty on turns and highway ramps, most of the time I am not brave enough to let the car go into the curve with its selected speed, so I take over and brake in the last moment.

I really don't understand what a driver should expect from Autosteer normally...

 

[beachmiles]

My M3 always reads and uses the truck speed limit signs which is usually 10mph slower than the car speed limit so my car will wrongly drop it's max by ~10mph and slam on the regen. Broken logic on speed limit sign reading.

 

[JolietJake]

YES! Just got my MYLR in Feb. been trying out FSD (3 month trial) and have had several wrong speed limit problems, both reading too fast and to slow. The most dangerous one was where a steep hill with a 15mph sign limit, ends at a stoplight to merge with a crossing 45mph divided highway. I slowed to a stop and FSD followed the left turn when the green arrow came on. Did a good turn, but with no 45mph sign on this part of road, It stayed in 15mpg mode while the tailgaters behind me were swerving around ( until I took over.). Not Ready For Safe Use.

 

[Marktm250]

On a recent trip from Houston to Canyon Lake TX, most of the speed limit signs were not recognized. A few in smaller town at lower speeds where recognized, but when on open rural roads going out of the lower speed limits, the signs were consistently not recognized - although in plain sight.
This resulted in AP being not only useless, but dangerous when switching on as the speeds immediately would drop - not matter how I set up the max speeds. I made this same trip a few months ago and and did not have this problem, so wondering if a recent a "upgrade" degraded the AP - making it essentially useless.