This photo shows the aisle between rows of stalls in a center aisle barn. The roof over the aisle in this barn is fitted with clear roof panels to allow lots of light into the barn. Keeping a stall aisle clean and clutter free is a great insurance policy in the case of a horse panicking while being walked in the aisle and even in preventing barn fires. This barn aisle is swept daily and clutter in front of horse stalls is kept to a minimum.
Rubber mats in the center aisle help create a safe way to crosstie a horse in a concrete aisle. Concrete can be very slick, particualrly for shod horses, so laying heavy rubber mats in areas you expect to tie or crosstie horses is an excellent and relatively inexpensive option. A pricier but more aesthetically pleasing option for center aisle footing that has excellent traction is rubber pavers which are laid like brick, but provide excellent traction for horses both barefoot and with shoes.