This is the most recent Gridmap released before the v0.4.3.x Gridmap which added some offroad terrain, vegetation, and a high-speed loop around the perimeter. Some users have problems with the new map. This will not overwrite the current Gridmap or Scenarios. It adds stand-along items in the Freeroam and Scenario menus such as "Gridmap v0.4.2.2" and "Jumps v0.4.2.2".
You won't have to use the v0.4.3.x Gridmap but you will still have the option. The included v0.4.2.2 Gridmap level is entirely self contained and does not use any resources currently shipped with the game. This means that features such as the large jump are present despite the current (at the time of this writing) error in the 0.4.3.x Gridmap reported here.
If you'd like to remove the v0.4.3.x Gridmap entirely simply follow these instructions and omit the final step (do not Verify Cache unless/until you want the new Gridmap back).
Credits: All resources in this map are from the BeamNG team's v0.4.2.2 release.
Installation: Download the zip file and place it in C:\Users\%USERNAME%\Documents\BeamNG.drive\mods