Planning and transportation leaders from across the tri-state area met at the Waldorf Astoria today for the Regional Plan Association’s annual gathering, featuring panel discussions and a keynote by Mayor Bill de Blasio that was noticeably light on transportation issues.

The mayor’s speech was a bit of a coming-out to the city’s planning community. “Planning is not a luxury; it’s a necessity,” he said, later quoting Daniel Burnham to the crowd of regional planners. “I think of environmental sustainability in the same breath as economic sustainability.”

“We haven’t fallen into the trap of thinking that we can expand ever-outward,” de Blasio said. “Here in New York City, we have to be smart. We have to be efficient.”

Not surprisingly, the mayor made income inequality the fundamental theme of his speech, but he also noted the limits of local action in the face of a federal government he described as absent. “It’s better addressed in a regional manner, and better still in a national manner or international manner,” he said. “We’ll do it locally, until the day comes when the paradigm shifts.”

Transportation Commissioner Polly Trottenberg came to today’s event, but that issue was mostly absent from de Blasio’s speech. Aside from lamenting the federal government’s slow fade from transportation investment, the mayor did not outline his vision for how transit links to inequality and environmental sustainability. Vision Zero went unmentioned, as did the long commute times facing some of the poorest outer-borough residents.

Instead, de Blasio talked up his administration’s goal of building and preserving 200,000 units of affordable housing in 10 years, calling the plan to achieve that goal, which is due next week, “extraordinarily ambitious.”

Although transportation didn’t take center stage at today’s event the way it might have in previous years, when congestion pricing or DOT’s bike and pedestrian programs took the limelight, it did feature in a number of breakout sessions, including one on traffic safety and another on transportation funding. And today’s assembly was a stark contrast from last year’s, when RPA heaped praise on the Tappan Zee Bridge project.