Highway hypnosis is a mental state where drivers are less alert and are barely conscious of their actions. Another way of saying it is that drivers are on autopilot. They are still driving the car, but their mind is not fully engaged in what they are doing. They react much more slowly to external stimuli, such as other cars.
Highway hypnosis commonly happens on long drives, especially when there is little change in the scenery, or you are taking a familiar route you have taken many times before.
This condition is also called white line fever, and the main reason it is so dangerous is that drivers do not realize it is happening. Sometimes drivers do not “wake up” to what is happening until they are about to get into an accident.