Tunnel vision is when your field of observation becomes narrower and you do not detect movements in the periphery in the usual way.

A degree of tunnel vision is inevitable when you drive 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.

Read more about country driving hazards