This is only partially related but this NASA article says with their aerodynamic technology a truck can save almost 7000 gal of diesel a year.
If we assume (just to get ballpark numbers) a semi gets about 5mpg and drives about 100k miles a year that’s about 20k gal of fuel.
Don’t truckers (at least in the US) often own their truck? I would assume that being more of a constraint than the aerodynamic tech itself
https://www.nasa.gov/offices/oct/40-years-of-nasa-spinoff/tr...
