I know it not true gray scale.
But I'd I remember correctly it drops some of the colors and some of the information displayed as well

Also I don't think you can get sat view.

If you go to menu and turn traffic off, the turn night mode on it is "different"'than traffic view.

For instance turn on night mode set the view to 3D then go to the mile scale. Look atvthe sky, it will be dark, turn off night mode and it's blue.