system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are trailer tractors so boxy and non-aerodynamic?

So, first of all, there's a shape difference between tractors in Europe and the ones in the US. EU ones are pretty much a flat surface slamming against the wind at 100+km/h. US tractors have a front mounted engine, which gives them a seemingly more aerodynamic shape. However, when brought together together in the same plane, the engine and the windshield have roughly about the same surface area, with both surfaces being mostly flat. I don't know if the US trucks are more aerodynamic or not, so some input on this would be nice, as well.

The overall question, however, remains: how come aerodynamics doesn't play a role in truck development? Considering the fuel costs, the large front surface area and the speed they cruise at, you'd think aerodynamics would be something truck manufacturers should be all over.
gpt
EU tractors generally have their passenger cabins mounted on top of the engine instead of having the engine be in front of the cab. This makes the tractor look much boxier than American styles but it also makes them shorter. Being shorter is much more important in Europe because many cities have small roads with tight corners that aren't as common as in America.