Drift Zones provide information about the nature of a space and people’s movement through it, such as the level of the terrain and any necessary changes of direction or changes in walking speed. In some circumstances, notably long corridors, they may be more appropriate to use than Focal Drift Zones. They are useful as a supplementary routing measure in areas of high congestion or anomalous situations where Entity movement needs to be ‘corrected’ from that created by LEGION Auto-navigation.

Drift Zones have an area, a directional arrow and can filter by Entity Type and Target. They are generally used for modelling the following:

• Long narrow corridors, generally for corridors of 2m width or less.
• Stairs and escalators in rare occasions when the specialised Stair and Escalator objects are not sufficient.
• Boarding areas in front of ‘ad-hoc’ stairs and escalators when the specialised Stair and Escalator objects are not sufficient.

Drift Zones are also useful in the following cases:

• ‘Keep left’ signs
  • In instances where signage results in people moving in an absolute direction (to the left or right) as opposed to towards a point (represented by a Focal Drift Zone).
• Heavy two-directional flow
  • In corridors where very heavy bidirectional flow is expected, operational procedures to segregate that flow are best represented with two Drift Zones directing Entities in opposite directions (using filters to select Entities).

Drift Zone parameters

The parameters you need to set for a Drift Zone are numerous and fairly complicated, so this section contains four procedures for setting the parameters named Speed Change, Direction Change, Stairs and Escalators, Additional, and Availability Parameters.