blizzard, jrcarroll, and tjpohio,
Excellent illustrations of the situations one can encounter in doing this job - I have certainly run into instances where a 400 or 600 mile run will be the limit - because I have either been up all day, or for some reason didn't sleep all that well (woken up in the middle of my sleep, say), or just didn't get as much as sleep as I would have liked, prior to the load.
There are other times where, as you fellows state, you wake up well rested and immediately, or in a short while, get a long run - and you can go 1000 miles .... or more. Other times, you may get up early, and take a nap in the afternoon - and be in good shape to
go long.
Generally speaking, when I am out on the road working, running hard, the first and foremost thing that I try and attend to when completing a load is getting adequate rest for the next one.
When I finish a run, particularly a longer one, sleep generally comes before
anything else - getting on the computer, taking a shower, eating ..... or, in some instances, even bothering to take a dump
I have been known to sleep for 10 or 12 hours .... or more .... sometimes I will sleep for 6 to 8 hours and wake up for a few hours, or just a bit (minutes) .... and then go back to sleep for another 4, or 6, hours ..... or more. More often than not, I can make myself go to sleep - whether I am truly tired or not.
As a solo unregulated driver, one needs to get as much of it as you can, when you can - because you never know whether the next call will be for 100 miles .... or 1000 ......
As guido rightly points out, to some extent it is a matter of conditioning and self-discipline - many may not be aware of the extent which one can exert control over one's body, and one's mental state. There certainly are limits to the extent of human endurance - however they may be much, much more than what many have been led to believe.
In a former life, I was involved in a business which was very much deadline driven, where very bad things would happen if deadlines were not met. On more than a couple occasions I had to stay up working well beyond where I really would have preferred to - I'm speaking in terms of
staying up for days. The worst instance of it was one project I worked on where I had to stay up working for better than 3 days straight (almost 4 days), in order to meet a deadline.
I was able to do it - and was productive - and met my deadline. Interestingly, at some point into that fiasco, I was actually less tired than I had been at an earlier point - I guess that is what is known as a second wind. Of course, by the end of it, I was physically and mentally exhausted - and I needed to sleep and rest - but I wasn't falling asleep.
To some extent,
remaining interested (in one's environment, the task one is performing, etc.) can play a huge role in how one feels, and in one's mental state and level of alertness. Allowing oneself to become
bored with whatever one is doing, one's environment, etc. will have a definite adverse effect on one's mental state and alertness - it will actually make you tired. While it is not a substitute for adequate rest when you need it, remaining interested and avoiding being bored does help one to remain alert.
I would never suggest that individuals are capable of staying up for the amounts of time mentioned above and driving safely - I was in an office environment, working on a computer - and consequently posed no threat to the safety of others. It merely serves as an illustration of what an individual is potentially capable of, when necessity demands it.
To assume that 11 hours is the maximum that anyone can safely drive, in any circumstances, is in my estimation an unreasonable view - since, as a consequence of being arbitrary, it ignores data which are relevant to the question of
at what specific point is one unsafe ?
