Just read the website in detail. This system monitors every single aspect and action of a driver and vehicle, from route deviation to speed, idle, acceleration, braking, and location, among other things. All this data is available real time to a central location, (our District), who has the dashboard and software to isolate any vehicle's performance outside the "norm" they establish (acceleration, for example) or too much idling time or any deviation from line of travel (don't miss a parcel, you'll get an alert) Typically if the system "beeps" while being driven, an alert is sent to local office (PM) to investigate and take corrective action.
And you thought Big Brother was watching before! Every time you step on the gas, brake, or initiate a turn this information is being sent to central command, for comparison against a standard and a normal.
To the post office, "driver coaching" is written discipline.
Thanks to
@Gotrope and
@Cobrabuilder for the tip offs.