Soil cells are vertical webs at the corners of each individual cells which minimise girdling of roots along the interior cell walls by directing them downward. It's advantages is that it can support  the heavy load of vehicular such as fire engine access way, as well as preventing soil erosion. It does not hinder the root growth, minimise uneven surfaces and easily installed and replaced. This is part of the Green Building Certification and promotes Green Building.

Reference: http://www.bex-asia.com/__novadocuments/35099?v=635127361767670000