The risk of becoming speed blind is greatest on straight, wide and smooth motorways with little traffic while driving through open landscapes.
The biggest risk with speed blindness is that you underestimate how long it will take to lower your speed or stop the car completely. This can, for example, lead you to drive too fast onto a motorway exit, which may then cause you to drive off the road or misjudge the car's stopping distance and potentially drive into a vehicle ahead.