This is a dazed or 'spaced' state brought upon by the particular influences of driving a car on a decent highway, especially at night. The combination of the steady vibration, constant rushing noise, and perhaps the steady, metronomic flickering of lane markers and safety reflectors all contribute to a mellow and relaxed state or light trance.

Highway hypnosis can obviously be dangerous! Here are some suggestions for fighting it:

  • Roll down the window; the airflow and irregular noise will help. If the air outside is chilly, that will help as well.
  • Make sure your heat isn't up too high.
  • Play loud music.
  • Sing. I like this one; it forces you to do something and also makes you breathe more deeply. The resultant oxygen intake will keep you more alert.
  • Have others in the car talk to you. If you try this when you're alone, you really need a nap. Pull over.
  • Pull over and take a quick nap. This may not be an option in some cases, but if it is, why not? Car seats are comfy, and on most serious highways no-one is likely to molest you or your vehicle because there's no foot traffic. Just be smart; use a rest area, or pull all the way off the road. If you must use the shoulder, make sure you do so after a long straight stretch, so passing traffic has time to see you. Use hazard lights.

I am curious about this state, because I have entered it many times. What is nerve-wracking about it is that while I have been perfectly content while in it, I am always scared afterwards when I'm alert. This is because I realize that I have no memory at all of the last one, five or even twenty miles - and I have no idea how I would have reacted (or if I would have done so at all) to an emergency.

If you find yourself succumbing often to this even when you're rested, and/or you have a headache, STOP DRIVING YOUR CAR and have the exhaust checked. You may have exhaust gases leaking into the cabin. If you are on the road when you notice this, immediately roll down all the windows until you get home, then have your car checked.

Be safe. Get sleep, let someone else drive, whatever. Don't risk it.

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