1. Pushed my sleep limits 2 day before this drive, stayed up til 2AM, got up for work, had a coffee, normal Friday, took a nap later.
2. Had a normal Saturday.
3. Got up 3AM Sunday, picked up Troy, had a coffee while driving 200 miles to a bicycle show in MA, used Route 95. Good concentration, highway speeds around 80.
4. Had a nice day at the bike show.
5. Left for home around 1PM. Within 20 miles, began to have the thought that I could not complete the drive safely.
My attention began to wander. I would say that, at the very beginning, the sensation was as much physical as mental. I would look left at the scenery for a split second, then find I was a fraction slow returning my sight to the road.
The idea that concentration was in fractions of a second is vital here. A biologist knows that we are allowed about 20 to 25 per second to take in information. A good driver uses these to advantage. What seemed to be happening when I was getting "tired"-- I was lacking a kind of neck balance to keep my eyes where they were needed-- on the fast lane, slow lane, upcoming traffic, cars being passed....
There was no danger at this point, no swerving, no touching the lane-dividing paint. Another car would not have had a clue. A driver has to have this early warning system while becoming tired.
The moment I decided to take the next exit and stop was when I realized my attention was to the left for the good part of a second. In this second, 20 or so things went through my mind, and most of them were not about the situation at hand. So I knew. Again, there was no swerving, nothing external.
We stopped and I got a cup of coffee, walked around a bit, stretched. Remember, this was at 130 PM or so.
There are experts at safe driving who would maintain that, at this point, the only way for me to recover and drive the rest of the 170 miles home would be to take a long sleep session. I was open to this possibility-- there was no need to get home sooner than later. But, after the coffee (especially), I was more than alert, and drove home without any more mental wandering. All the demands of I95, the New York City bridges, the Long Island Expressway, and the other drivers were met at my usual standards.
The point? Well, it's always about limits. I know mine, and it seems they can be beyond what some experts say regarding recovering to a safe driver status after being tired. Perhaps this would work for another person too.
I would ask an interested reader to refer to four other blog entries here on the same topic. They are
1. Pop Your Ears
2. Nursing A Car Back
3. Returning From NC
4. twelve hundred miles... there and back again