WAY BACK IN THE TWENTIETH CENTURY, a bunch of Ivy League Professors sat around inventing space colonies. They were lauded as visionaries and went on as lecture tours. Do you think they thought about traffic jams in space? Somehow, we don't think they did. We're the G.T.A --- Galactic Travel Authority. The movers of the daily grind, circa 2075 A.D. And we're glad you're working for us now.