At the turn of the century, telecommunications had a centripetal effect on the topography of cities. It encouraged the separation of offices from factories and the consequent concentration of offices downtown. Thus telecommunications led to urban concentration. By the middle of the century, a more flexible and universally avail able telecommunications technology was used to escape urban concentration, with both homes and work places moving out of the city’s center and even into exurbia. In that period, the effects of telecommunications were predominantly centrifugal. In the fu ture, still more malleable communications technology is likely to give people more choices in how they use it. Until now, each of the trends and effects noted for communications could be simul taneously noted in transportation. Now, however, in the prospect of an energy shortage, one of the very likely uses of telecommuni cations may be to overcome some consequences of high energy prices. Most particularly, improved telecommunications may be used to offset the centripetal pressure for achieving energy sav ings by renewed urban concentration.