simplified answer to this is car drivers - let me explain
"a jack knife" as it is commonly called is the end result of an accident not the cause
this occurs when the unit of an articulated vehicle turns back on the trailer it is coupled to - to such a degree that it hits its own trailer - this means that it is that far round on its self that if the unit tries to drive forward the trailer will move backwards
have a look in your kids toybox and get a toy wagon and try this it will make more sense
now when this happens the truck cannot get out of this under its own power as no matter how much steering is applied it is effectivly past the point of no return and a recovery truck will need to drag the unit sideways to free it
right clear as mud - back to my first point car drivers cause jack knifes - how you ask - simple really - the quickest way to cause a jack knife is to brake too hard on a slippery surface and then swerve - youre getting it now arent you !
most interviews with drivers after one of these incidents site a car as the initial cause of the accident
and why do they cause so much disruption - it is simple again wagons are big and block the whole road and it takes a while for the recovery trucks to get to them to sort it out
when a car skids in the snow a couple of strong lads can usually push it out to get it going again - wagons are kind of big and heavy enough said !!
generally wagons are better in the snow as being heavier they exert a bigger ground pressure per area of tyre size and they cut through the snow where cars compact it
handy hint if you have wide wheels on your car and it is bad in the snow - go to the local scrap yard and find the narrow wheels off the base model of your particular car and that should help and should be reasonably cheap
bye for now and drive safe
