What is 'Inattentional Blindness' (Unaufmerksamkeitsblindheit) in human visual perception?

1. A permanent physiological blindness caused by eye disease
2. The darkness experienced when entering an unlit garage
3. The reflection of sunbeams on snow-covered roads
4. Failing to perceive an unexpected but fully visible object (such as a motorcycle or cyclist) right in front of the driver because attention is occupied elsewhere or focused solely on looking for cars