Just went and had a look for facts on stopping distances for trucks.
An 18 Wheeler requires 0.25 to 1.0 before the brakes are activated, from the time of brake depression.
I found this on a website and am unsure of its full truthfullness but i will continue like it is true.
So taking the maximum time it could take for the brakes to activate...1 second from the time you press the pedal, at 80km/h you've traveled an additional 22 metres.
Now...at 100km/h a truck, in optimum conditions needs apparently around 525ft (159, call it 160 metres) to stop.
Add on say 1 second reaction time thats another 27 metres. (because we're looking at 100km now, not 80)
So we come up with over 200 metres to pull up a roughly 30 Tonne weight up.
And if we say, yes, every car is leaving a 2 carlength gap between themselves and the next car (because they dont) its roughly 13 cars away that he'd have to be watching to make sure he'd be able to pull his truck up
(websites used for distances:
http://www.truck-accident-lawfirm.com/CM/Resources/Trucking-Accidents-Collision.asp )
PS...im not too good at mathematics and based all this on statistics and facts found from websites and i know, real world conditions are different, but yeah.
Im waiting for Minux to prove me wrong and call me all types of names, but atleast i'll learn something new