When they show up to the depot and get their bus assignment they get a slip with the PIN (IIRC), otherwise they can call dispatch back up, identify themselves,

When they show up to the depot and get their bus assignment they get a slip with the PIN (IIRC), otherwise they can call dispatch back up, identify themselves, and be given a reset remotely. (https://www.cleverdevices.com/products/secure-bus-access/ https://www.cleverdevices.com/products/secure-bus-access/)