Just found this post as I'm experiencing the same thing. Intermittently the speed sign on the dash displays as 18 in a 30mph zone, 24 in a 40mph zone, etc. So you're correct that for some reason it occasionally thinks the speed limit is in kmh for some reason and then converts that to mph to display on the dash. I don't know if that's because it's falling back to the sat nav, but it seems that once it starts doing it, it continues to display the speed limit incorrectly even when passing speed signs that are clearly visible. Very annoying as it's flashing away because according to it you're speeding!Do any other 500e drivers have issues with the intelligent speed assist system?, My La Prima seems to identify signs correctly, but after a period of not seeing a sign, it checks the sat nav, and it appears to convert the sat nav speed from km to miles..... So a 30 sat nav signal displays as 20 mph.... 60 as 40mph etc. Lovely car, but this software bug is very annoying, and Fiat does not seem to have any answers!!!