In article ,
Matthew T. Russotto wrote:

Usual wild guesses:

1391: It's a box containing a set of directions from Cincinatti, OH to
Dayton,OH. Google maps does not return the same set of
directions, even avoiding I-71, instead starting with a leg
north on Main, then right at 7th to Gilbert, left on Eden Park,
and only then to Reading.

I imagine it was mounted in a bus, or perhaps a delivery truck
or similar vehicle.

Replying to myself because I missed the obvious clue:
Perhaps it's for a mail truck. The first directions start "From P.O."...
--
There's no such thing as a free lunch, but certain accounting practices can
result in a fully-depreciated one.