The "Distinct Distances and Transit Times by Direction" in the global settings controls whether a separate distance and transit time will be maintained for each direction in the distance / transit time cache and distance / transit time overrides:
When this flag is True, if a distance / transit time cache entry is created for the combination of Location A and Location B, separate distances and transit times will be maintained for a movement from Location A to Location B vs. a movement from Location B to Location A.
When this flag is False, if a distance / transit time cache entry is created for the combination of Location A and Location B, the same distance and transit time will be used for any freight moving from Location A to Location B or from Location B to Location A. In this case, the distance and transit time that will be used with be the values returned when this pair of locations was first passed to the distance engine. If the original request was to identify the distance and transit time from Location B to Location A, then those values will continue to be used for distance / transit times in either direction until the cache is cleared or an override is defined.
When the flag is True, the Distance / Transit Time Override Properties page displays two separate sets of distances and transit times.
Recommendations when Distinct Distances and Transit Times Feature is Enabled
By default, the feature that allows distances between locations to vary based on direction will not be enabled.
If the "Distinct Distances and Transit Times by Direction" flag in the global settings is enabled, administrators are advised to also do the following:
Activate the Location 2 to 1 Distance and Location 2 to 1 Transit Time columns on the two versions of the List of Transit Time Overrides.
Clear the distance / transit time cache for all distance engines to force re-computation of data for each direction for any given pair of locations/addresses.
Review distance / transit time overrides for cases where the Distance or Transit Time between the two locations should be different, depending on direction.
Recommendations when Distinct Distances and Transit Times Feature is Disabled
If the "Distinct Distances and Transit Times by Direction" flag is disabled after being enabled for a period of time, administrators are advised to also do the following:
Deactivate the Location 2 to 1 Distance and Location 2 to 1 Transit Time columns on the two versions of the List of Transit Time Overrides.
Clear the Distance / Transit Time cache for all Distance Engines to force re-computation of data for each direction for any given pair of locations/addresses.