I remember when the Volvo FH was launched a bit of a song and dance was made about it being styled in a wind tunnel to give it the lowest drag of any tractor unit at the time. thus giving improved mpg. Since then however newer models from other manufacturers have been more square in design like the MAN and the Merc. Is it the case then that when pushing a big brick shaped object through the air rounding off the corners does not have a big effect?.
NB12:
I remember when the Volvo FH was launched a bit of a song and dance was made about it being styled in a wind tunnel to give it the lowest drag of any tractor unit at the time. thus giving improved mpg. Since then however newer models from other manufacturers have been more square in design like the MAN and the Merc. Is it the case then that when pushing a big brick shaped object through the air rounding off the corners does not have a big effect?.
It doesn’t really matter with a lorry, the tractor unit can be as streamlined as you like but stick a ribbed tipper or ribbed container and all the testing is in vain.
You see folks spend thousands on new fancy trucks, spend hundreds on painting them and then stick a set of spotlights on the roof or super singles on the front 
On a similar subject I’m very impressed with the way the new Scania is designed. The side windows and mirrors just don’t seem to get dirty, and the cab remains remarkably clean too. My old ones mirrors and windows used to get filthy. Intresting since they hardly look that different.
The air deflectors on the FL do a good job of keeping muck off of the door handles.