1:.:Extract TextureLoader and HD.tpf files into your Driver Parallel Lines game folder.
2:.:Open TextureLoader, click on Folder icon, click Browse and select DriverParallelLines.exe
3:.:Now in TexLoader click on small Folder icon, click Browse and select HD.tpf
4:.:Click on Run!
5:.:Thats it

Note:
At first launch it might take a little bit longer for the game to launch, in order to load new textures!