SCS Software announces they are working on Steam Workshop support for American Truck Simulator and Euro Truck Simulator 2, which will add the ability to share customized trucks. Here's a bit:

We are working now on update 1.23 for ETS2, and 1.2 for ATS. One of the major features coming with the updates is support for Steam Workshop. This feature is a really long time coming, considering that all of our projects always were popular for user modifications.

Right now our Workshop is still in limited testing. Some of our testers are passionate modders in their own. Even during testing there are already some cool mods appearing.