Paid trips, pickup distance, and empty running
Passenger kilometres are only part of a rideshare driver's route. Travel to a pickup, movement between demand areas, cancelled pickup travel, breaks, refuelling detours, and the drive home can all consume fuel without appearing as paid trip distance.
Use trip records, an odometer, or a route log to estimate both distance groups. If you know only the full distance driven, enter it under paid distance and set unpaid distance to zero; the fuel total remains correct, but the split will not describe vehicle utilisation.