The back up camera is decieving. When I first got mine (first backup camera I had), I thought I had alot of room behind me, but really the other car was pretty close. I think those lines do represent a distance, but I am not sure the interval. Once I realized that you can see the bumper in the camera image, it helped. I turned off that grid as it was screwing me up when parellel parking, which I have been doing for years effortly.