[bigfatkitten]

> You'd literally need to build more roads, as long haul trucks would be on the road, literally, for an entire day longer per load. Speed is efficiency.

Only up to a point. The relationship between speed and fuel burned is not linear, and fuel is the largest cost.

The legislated maximum speed for heavy vehicles in Australia is 100km/h, but most major fleets electronically limit their vehicles to 90 for efficiency reasons.

Every extra km/h over 90 has a negligible impact on trip time while imposing a large penalty in terms of fuel burn.