I was going to say add a trailer with sideskirts to the game becasue a lot of these trailers have been showing up in America, but I guess it is really an aero accessory: http://www.atdynamics.com/products/trailer-skirts/
I hope to see these added to not just owned trailer (if that feature will be available) but also preinstalled on company trailers as well, randomly added accessories perhaps.
Also would be neat to see the sideskirts flap a bit in the wind, since I am talking about wind, I have made a previous suggestion about "wheel flap physics" so the wheel flaps will move as you are driving along.
18 Wheeler: American Pro Trucker on the Sega Dreamcast and Nintendo Gamecube are able to simulate wheel flaps swaying away. If those systems can do it, then a modern errr.... "Economy" Computer should be able to handle this easily.
There is just something awesome about driving along heading towards the sunset on a one lane road in the middle of a desert with your wheel flaps swaying in the air.