When you drive at high speed, your field of observation becomes narrower and you do not detect movements in the periphery in the usual way, this is called tunnel vision.
A degree of tunnel vision is inevitable at high speeds. In order to counteract the risks associated with the phenomenon, you must actively scan the area alongside the road, well ahead of the car, for potential hazards such as pedestrians or wild animals coming out of the forest.
Tunnel vision can both arise and worsen because of fatigue, alcohol, stress, narcotics, inappropriate medication or diseases such as migraines.