There is a very effective mechinisim for providing a solution to this!
It is called "The Market"
Now, whilst I do not believe it is in any way infallable, It can, neverthless, on occasion, be effective at producing practical solutions!
So!
I propose a new class of comercial vehicle (Class <whatever>)
This new class will be granted the same speed allownces of private cars (IE No 56 MPH limmiters, No 40MPH restriction on NSL single carrageways etc)
However, to qualify the Tractor/trailer combinations need to be capable of achieving;
1) 3 successive "emergency" stops in quick sucession from 70 to 0 MPH with a full load achieving 0.9g deceleration, (Dry road) allowing 120 secs to build up speed betwen runs (Or what ever is needed under hard acceleration)
2) capable of maintaining a speed of 40MPH up a 1:9 hill!
Let the Engineers commense battle! And the Haulage industry beat a path to their door!
