That would be the US EPA and whomever influenced them in the Carter administration to classify trucks as regulated differently than other passenger vehicles. It unironically financially encourages SUVs over vans and bigger bodied trucks over smaller ones.
It’s killed the work truck, the small truck, and literal pedestrians.
Their intentions were fine at the time and it has resulted in average miles per gallon within their class going way up but it needs to be amended. The shifting of sales eats into any fuel efficiency gains. Regulate them the same as any passenger vehicle and give me my utility back.