In warehouses the materials handling equipment (MHE) such as forklifts, counterbalance trucks etc, operate in two distinct areas of traffic movement; Free movement and Defined movement.

In free movement areas the MHE can travel randomly in any direction. These areas are typically wide aisle racking installations, factories, retail outlets low-level storage, marshalling zones and food distribution.

In defined movement areas the vehicles use fixed paths typically associated with high-level storage racking with very narrow aisles.

These distinct movement areas require different surface regularity specifications and as such use different survey techniques to define the limiting properties.