Thank you Henrik!
In our case, we do not have the driver-id from the GPS devices. The typical case is that a driver may have one or more private car(s) and a company car, all owned by the company. The driver will be using the 2-3 cars dependant on type of activity.
I think the solution needs to support the option for the driver to select a car/vehicle and then create the journal for the trips.
Please also note that a driver may have different roles in the system, even administrative roles.
Your answer to catpl regarding the Administrator is somewhat confusing: What do you mean by Administrators in this case? Which specific rights do you need? And will he see all trips for all vehicles (users with _Unit role) driven by drivers (users with _DriverJournal Role) based on driver-id AND the default vehicles linked to these drivers?
Please try to clarify the conceptual idea and the terms used: Driver, Vehicle, Administrator, Trip, "User with _DriverJournal Role", etc.
Thank you! This solution has great potential but still needs some tuning.