If you are lucky, and rarely is this the case, then you may be on the
receiving end of what is only known as the "Ideal Situation." This
situation is, of course, the presence of one urinal. The etiquette here is
simple: if it's empty, pee, if it's not, don't. Period. Of course, a
foray to the world of the public stall could be merited if the urinal is
busy, but it is always preferable to busy one's self with washroom related
activity while waiting for the urinal to free up. Wash your hands, check
your hair, check the floor for loose change, do the moonwalk, etc.
An important note: It is NOT considered proper
etiquette to enquire to a peeing person if he is almost done. Nor is it
seemly to attempt to peek in the urinal for activity. If you suspect the
patron is merely standing around with his fly open, it is usually best
just to keep those suspicions to yourself.