> Given that they are in residential areas (and thus, in proximity of kids playing outside) far more often than UPS/Fedex...

That isn't the case at all in my experience. In any neighborhood I've ever lived in, you see at least one van from each organization come through daily. And if anything, UPS and FedEx come through more than once per day sometimes, whereas USPS doesn't.

Per your earlier point about freight I can imagine that UPS/FedEx have a lower percentage of company traffic in residential areas than USPS does. But I find it difficult to imagine that the total number of trips to residential areas is lower for them. They simply have more non-residential traffic than USPS, not less residential traffic.

I wish there were publicly available data on this stuff, as we can only discuss anecdotes. In any case, in the neighborhoods I've lived in, it's not uncommon for UPS and Fedex to have zero deliveries at least one day of the week.

If Fedex is rolling around twice in one day, it's never the same line (that is, Fedex Express vs Ground/Home; Express incurs a special surcharge for residential deliveries and thus is usually only used by companies that primarily deliver to commercial addresses or who don't care about cost).

UPS is similar; usually, they only roll around in the evening, and when they roll around in the morning it's for one package with a specific delivery window obligation.

During December, of course, this goes by the wayside. Even USPS will roll around twice a day on the weekends leading up to Christmas.

> That isn't the case at all in my experience. In any neighborhood I've ever lived in, you see at least one van from each organization come through daily. And if anything, UPS and FedEx come through more than once per day sometimes, whereas USPS doesn't.

USPS doesn't deliver freight, UPS does. So yeah, you are going to see both in a residential setting but you won't see any USPS trucks making freight deliveries in an industrial area. UPS has to support that use case, USPS doesn't.