FUTON indeed.  I deprodded it because the cited city document spells out a series of reasons to consider the street notable. Confirming additional sources for those may take time and digging, but such sources seem quite likely to exist.  I note that a couple of Portland history websites provide promising avenues for research, for anyone able to take up the task.  If the quotes at Cafeunknown.com are accurate, the local papers made a succinct case for the notability of the 1925 lighting: "From the standpoint of illumination per square foot, the Broadway association announces, Broadway will be the best lighted street in the world." (Sunday Oregonian, November 22, 1925.) "Gay with iridescent brilliance of the Milky Way, the main boulevard of the City of Roses will burst Tuesday evening into a dazzling orgy of electric rays that will rival the most famous glittering thoroughfares in the world." (The Portland News, November 24, 1925.)  
And PDXHistory.com has an excellent page about Broadway, which perhaps ought to be listed as an external link here.