A new study by UCLA has identified a subsection of pickup truck drivers that have even smaller penises than the average truck owner: men with lifted trucks. The conclusive findings clearly show that there is an inverse correlation between truck size and penis size.

“It’s pretty simple,” head researcher Timothy Dunkirk stated. “The bigger the truck, the smaller the penis. An easy way to remember is: truck tall, penis small.”

Notably, the study also found that men who outfit their diesel trucks to belch out a giant clouds of black smoke – also known as “rolling coal” – often suffer from undescended testicles; or have none at all.