[DH]

Gee, I can instantly tell that your are either an EX postal employee or a current one.

Am I right? Sure I am.

I hate to bust your bubble but “when you were a kid that carrier probably handled 200 pieces a day” is a pathetically stupid statement. That carrier served much larger area than you give him (or the real postmen back then) credit for. You have to remember, that was back when postal employees actually worked for a living.

[muawiyah]

You are attempting to start a flame war. Alas, you just don't have enough writing capability to do that. So, when your letter carrier was covering a larger area on foot he needed a relay box for the mail, else he'd had to carry it the whole way. Some other guy drove around dropping mail for that route in the relay boxes.

Given that there's a very clear trade off in work time between office and street, and that office time, and parts of street time are further categorized as having something to do with administering what's going on, or sorting and handling mail, any given route is going to have different opportunities for productivity improvement.

Turning foot routes into motorized routes enabled every carrier to handle more mail volume, and to get through the route faster. Adding 9 digit zip codes allowed USPS to use machines to sequence the mail for the carrier routes ~ which cut back on office time required to case the mail.

Anyone who's had the slightest experience with carrier service knows these things ~ there are no secrets. The fact you mention none of them suggests you simply don't know enough about the topic to discuss it rationally.