As I understand the WT & Awake have been printed in Canada for Canada & USA, it would seem that more trucks & drivers should be required.
While maintenance and fuel is expensive, WT has its own mechanics and drivers (unpaid) and fuel costs are the same whether used in their own trucks or by a private carrier.
I would expect that long haul trips would initially be full trailer loads but the load would become lighter as deliveries are completed, farther away from home base. Return trips are likely empty unless a pick-up of paper, ink or other supplies can be arranged on the way back. If travelling empty, then the trip is further overhead.
Perhaps WT is intending to reduce/eliminate much of the printed literature, instead forcing r&f witnesses to download at least their personal materials off the JW.org website.