Gothamist did a great interview with Robert Caro, who might be the foremost expert on Robert Moses. Here's a quote from the interview:
"I remember his aide, Sid Shapiro, who I spent a lot of time getting to talk to me, he finally talked to me. And he had this quote that I’ve never forgotten. He said Moses didn’t want poor people, particularly poor people of color, to use Jones Beach, so they had legislation passed forbidding the use of buses on parkways.
Then he had this quote, and I can still he him saying it to me. “Legislation can always be changed. It’s very hard to tear down a bridge once it’s up.” So he built 180 or 170 bridges too low for buses.
We used Jones Beach a lot, because I used to work the night shift for the first couple of years, so I’d sleep til 12 and then we’d go down and spend a lot of afternoons at the beach. It never occurred to me that there weren’t any black people at the beach.
So Ina and I went to the main parking lot, that huge 10,000-car lot. We stood there with steno pads, and we had three columns: Whites, Blacks, Others. And I still remember that first column—there were a few Others, and almost no Blacks. The Whites would go on to the next page. I said, God, this is what Robert Moses did. This is how you can shape a metropolis for generations."
Robert Caro Wonders What New York Is Going To Become