> The busses lock down with a PIN when they get out of the seat (generated that morning at the depot)...

How do drivers remember their daily PIN?

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/)