I’ve mentioned this in other posts and people have said it’s due to certain lighting conditions. But it’s just not logical that you can drive a car (especially a road car) and not be able to see what speed you’re travelling at. Some of the cars I have been in real life and I know that I could always see the needle regardless of the lighting conditions. Also, when it happens in a pure race built car the manufacturers would not bother to put in dials that cannot be seen by the driver as this would just add unnecessary weight to the car. And finally, every time I cannot see the needle I can always see the numerals on the dial. So, if I can see the numerals why can’t I see the needle. It’s just illogical.