How is the departure time determined?
A stop ends when the vehicle exits the fence. The default setting is to take the first measurement point outside the geofence as the end time of a stop. This can be changed if necessary, for example if you are working with devices that do not transmit frequent GPS data, which would give an inaccurate result.
Analysis in case of problems with the departure time
Problem: Departure is not registered
This does not happen very often if the arrival at the stop is registered. Below are some possible causes if it does happen:
- The GPS might have failed during the stop, or the driver might have logged off, thus losing connection.
- The driver is extremely early or late (although in those cases, usually the arrival is not visible either).
- There are two adjacent (un)loading locations, and the vehicle remains in the same parking spot. So only one stop is visible and it looks like the second one did not take place.
Problem: Departure is registered too early
- This can happen when the driver briefly leaves the geofence during a stop and then enters it again, for example because of a break or because of a detour between unloading and loading. This can be solved by drawing geofences more generously and by setting the maximum 'too early' value correctly.
- It can also be a consequence of 'GPS drift', making the location observation inaccurate and varying, while the vehicle is in fact standing still. If one of these points falls outside the geofence, the stop is incorrectly seen as ended. This risk can also be reduced by drawing in geofences generously (where this is possible).