Metro, a regional planning authority, has written and implemented the nation's strongest and most comprehensive smart-growth plan in Portland, Oregon. For a region expected to grow in population by 80 percent in the next five decades, Metro's plan calls for a mere 6 percent expansion of land area; high-density housing in the form of apartments, mixed-use developments, and single-family homes on small lots; pedestrian-friendly design codes; 125 miles of rail transit; and almost no new highway construction.