The "part4.rar" suffix indicates this is part of a . To successfully extract the game files, you must have all parts (e.g., part1, part2, etc.) in the same folder and use an extraction tool like WinRAR or 7-Zip on the first part.
The city of Hannover, Germany, was completely rebuilt from scratch with a fresh look and updated layout. Euro Truck Simulator 2 v.1.45.3.0s.part4.rar
Added a option that automatically adjusts wiper speed based on rainfall. The "part4