The layout of the store may make switching to a single line tricky. You need enough area for people to line up, and stores I've seen with this layout usually h

The layout of the store may make switching to a single line tricky. You need enough area for people to line up, and stores I've seen with this layout usually had a larger area between the aisles and registers than most grocery stores. Also the largest big-box stores would have to go with multiple multi-register lines due to the sheer number of registers.