How Speed Assist Works
Model X displays a speed limit on the instrument panel and you can choose if and how you are warned when you exceed the speed limit. Also, instead of using the detected speed limit, you can base warnings on an arbitrary speed limit that you enter manually.
In situations where Model X is unable to determine a speed limit, or if Speed Assist is uncertain that an acquired speed limit is accurate, the instrument panel may not display a speed limit sign and warnings do not take effect.