Update ETS 2 with the new patch 1.3.1. It will install the official brands for Volvo and Iveco trucks (instead of Valliant and Ivedo). Your hired drivers should now be able to find easier a job on their way back to the office, and the developers added a retarder (manual or automatic).
Other appreciated fixes and enhancements are listed along the dowload links at http://www.eurotrucksimulator2.com/update.php. Don’t try to update if your licence is not “official”, the game is now proctected and rejects you at the launch online key check.