I went to the Main library and looked up Robert Moses’s “Arterial Plan for Pittsburgh.” There are multiple copies, in the Pennsylvania section. They seem to be the original reports submitted by Moses and associates in response to a request by Heinz (which Heinz, I’m not sure).
It makes for interesting reading. I photographed the pages, which are decaying and put their images online here. I don’t have a good way to make a shareable document or scan the pages for OCR; in any case, there are words missing since some of the pages have grown brittle over the years and split.
If you read the introduction, you’ll see a fine example of Moses’s false modesty and contempt for long-range planning. “When Mr. Heinz first asked me to give an opinion on Pittsburgh’s arterial problem, I was not inclined to assume this responsibility, not only because of absorbing work in New York, but because of an abiding dislike of long-range experts. In this case, I finally agreed to advise the Pittsburgh Regional Planning Association, acting merely as a diagnostician who applies to the local problem whatever judgment, knowledge and practical experienced he may have gained in dealing with similar problems elsewhere.”
There is a lot here that guided Pittsburgh’s design up until now and probably continuing for a long time. The Parkway East is his, as is the Cross-town Boulevard (and its effect in separating Downtown from the Hill District, the center of a vibrant nationally-important black culture at the time, which he dismisses as a slum). And the “entrance” to Pittsburgh is his, too, though I think he was thinking of a different approach than from the Fort Pitt tunnels.
There’s also this lovely thing, which he thought should be placed where the fountain is at the Point: