Actually having a smooth undercarriage and a smooth transition from truck to trailer and some wind breaking fins reduce drag a lot. https://en.vda.de/dam/vda/p

Actually having a smooth undercarriage and a smooth transition from truck to trailer and some wind breaking fins reduce drag a lot. https://en.vda.de/dam/vda/publications/FAT-SCHRIFTENREIHE%20260/1384523963_de_344759559.pdf https://en.vda.de/dam/vda/publications/FAT-SCHRIFTENREIHE%20... And the front aerodynamics dépend more on the details than it's length. Some aerodynamic designs have shockingly steep fronts. https://en.m.wikipedia.org/wiki/Schl%C3%B6rwagen https://en.m.wikipedia.org/wiki/Schl%C3%B6rwagen