I'm Not Sure That I Buy That This Increases Sustainability
According to this recent blog post over on Core 77, Walmart (Canada)'s New Supercube Increases Sustainability by Designing Bigger Trucks. Working with an Ontario-based Company called Innovative Trailer Design, they have commissioned the Walmart Supercube that can hold 30% more cargo in the same footprint. By designing a truck with a squashed cab, they can increase the trailer length from 53 feet to 60 feet without increasing the overall vehicle length. Plus, they are lowering the floor of the trailer and installing a built-in scissor lift to help load the cargo into the far reaches. And they've even added a dromedory box that holds an additional 10% of cargo behind the cab that can be independently loaded and unloaded.
Now, technically, if there is no significant difference in fuel usage, then the trucks will be a more sustainable way to move cargo since you will now only require 3 trucks to move what used to take 4 trucks, but if the total number of trucks on the roads do not decrease, then there is no significant advantage.
Plus, more cargo = more consumption, and that's never an argument for sustainability.
It's a great concept, and a cool design, but I'm not sure I buy that it's going to improve sustainability.