Speed and distance
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 BMW X3, 2016 BMW X3, 2015 BMW X3, 2014 BMW X3, and 2013 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.
At high speeds and when a sign is still at a considerable distance from the vehicle the system may exhibit a sporadic inability to recognize the sign. As these two variables become more pronounced, so does the probability of failure to recognize signs. The effect is more pronounced during night-time driving.