Why log tag logins?
Every report that names a driver depends on the tag read at the start of the trip. A trip with no tag cannot be assigned. A shared tag assigns it to the wrong person. A tag on a vehicle the driver is not set up for may mean a swap nobody approved. This log checks the login data before anyone uses it.
How is each trip read?
The shortest trip that counts ships as 0.5 km, the target as 95 percent and the reader-check share as 60 percent. All three are typical values you replace with your own.
How are shared tags found?
A tag cannot be in two vehicles at once. The log compares each trip with every other trip of the same tag. If another vehicle has a trip that starts before this one ends and ends after this one starts, both trips show Shared tag. A trip whose end time is earlier than its start time ends the next day, so trips that cross midnight are compared too.
Is it the reader or the driver?
One driver forgetting a tag is a habit. Many drivers with no tag on the same vehicle points to the reader: its wiring, its connection to the device, or the device configuration. The By vehicle sheet flags a vehicle when its no-ID share reaches your reader-check value. Check the hardware before you talk to the drivers.
Why do tag numbers not match?
The number printed on a card, the number a reader sends and the number a platform shows can differ: decimal or hexadecimal, with or without leading zeros, or in reversed byte order. If a known driver shows as Unknown tag, convert the number before you blame the driver. The Driver-ID Card and Key Number Converter on this site does that.
Limits
The log works on the trips you paste. It does not read your platform, it does not prove who drove, and it does not cover driving hours or driver scores. Use it to clean the login data that those reports depend on.