ATD stands for “actual time of departure.” It is a metric used to determine the speed of logistics, i.e., how quickly goods are moved from one location to another. This term can be applied to both material movement and human activity.
When using this term for humans or other animate objects, ATD refers to the actual time that it takes for workers to begin an action after receiving instructions. For example, if a dockworker ship arrives at his/her station two minutes before shift starts but does not tie up the boat until ten seconds before shift start time, then their ATD was eight minutes. When used in regards to transportation vehicles ATD refers directly to “cargo door-to-door” transit time (i.e.; departure – destination) without regard to any associated loading and unloading time. ATD is commonly used as a term in transportation routing and planning to define transit times (time) between ports, for example: Miami – New York (3 days), Seattle – Rotterdam (14 days).
In the context of logistics management, ATD is used as a measure of service level. The higher the number, the more dependable the shipment schedule. However, there are two ways to look at how this number can be interpreted:
As mentioned above, actual time of departure refers directly to cargo door-to-door transit time without regard to any associated loading and unloading time. In this case, it would be three days from Miami’s port to New York’s port, with no associated loading and unloading time.
Actual Time of Delivery refers to actual or guaranteed transit times for a shipping company or mode of transportation that includes all necessary steps in the supply chain such as the pick-up from the supplier/manufacturer, transportation operations, customs clearance and any required unloading at destination (port, station etc.). Anything beyond this would be considered “in addition” to ATD which is commonly referred to as TAT (time and a half).
In this case it might take three days to move goods from Miami’s port to New York’s port plus two additional days due to unforeseen circumstances involving customs processing after delivering into New York. Hence, for this example ATD would be seven days and TAT would be five days.