Complex sentence: An example of a Hypervigilant state is a driver who has previously been involved in a car accident may devote so much attention to road conditions and other cars on the road, that he or she does not hear an accompanying passenger while driving.
Split into simpler sentences: An example of a Hypervigilant state is a driver who has previously been involved in a car accident. The driver may devote so much attention to road conditions and other cars on the road, that he or she does not hear an accompanying passenger while driving.