Cub Driver wrote:

(And if you get a DC cab, settle the fare in advance. They don't use
meters in DC so that the Congress can set fares totheir advantage. VA
bans them from picking up fares, at least at Washington National, but
the cabbies used to hang around pretending to adjust things in the
trunk. Travelers in the know would get a cheap trip back into town.)

DC cabs can pick up fares to go back into DC or Maryland. They just
can't pick up people to go to Virginia from National. At DULLES, only
the Washington Flyer cabs are allowed to pick up at the terminal
(although the FBO's contract with others local companies).

The DC cabs all have a map that shows the fare zones. Of course, if you
are not familiar with the layout of the city, it's probably a mystery to
you.