The Online Drivers page (Operations tab, then Online Drivers) shows all Drivers and their status as either online (logged into the voiceERP app) or offline (not logged into the voiceERP app).
At the far right of each Driver’s row, you will see an Actions column and, in this column, you can click the symbol (three vertical dots) and force that driver to log out of the voiceERP app by clicking Force Logout. Drivers cannot log themselves out of the voiceERP app. The voiceERP app should automatically log out ~30 minutes after returning to the station and hitting the geofence.