Few people have had a greater impact on the look and feel of New York City than Dan Doctoroff. As deputy mayor of economic development for the first six years of the Bloomberg Administration, he presided over the fine-grain rezoning of 40% of the City, as well as the mega-projects that have come to define 21st century New York.

This is part two of my Q&A with Dan Doctoroff, who recently published a memoir, Greater Than Ever, about his time in the Bloomberg administration. In part one, we discussed the City’s post-9/11 transformation. In this installment, we look to the future of transportation and technology, and discuss Donald Trump’s temperament.

A mantra today among urban economists is to get rid of zoning and build more. The Bloomberg administration made a massive effort to rezone the city—affecting 40 percent of its total area, and adding hundreds of thousands of jobs and housing units, including 165,000 units of affordable housing. What’s your take on zoning and building codes? Should we get rid of them or massively deregulate them as the market urbanist say, or should we use zoning to grow better and more strategically?

I think we found a middle way between overly restrictive zoning, like San Francisco, and little or no zoning at all, like Houston. We believed thoughtful zoning and building codes are essential and the process has to be democratic and community-based, but that it should be led by a City Hall that exerts strong leadership, particularly where broader city-wide issues are at stake. While we found the process of getting our rezonings time-consuming and often frustrating, I can say without hesitation that in every one of the 140 rezonings, we benefitted from significant community engagement.

Cities clearly need to do a much better job of making zoning a more dynamic, ongoing process that assesses what the needs are in the context of the times we live. Housing is the best example, where I think most urbanists would agree that the best answer to high housing costs is to dramatically increase the supply of land available for housing. In New York, we were able to do some of that by opening up areas that were previously zoned only for industrial or commercial uses.

In the future, technology may enable cities to ease zoning and building code rules through performance-based measures. For example, whereas today we might say you cannot have a music studio next to senior housing, someday we might be able to say that you can do whatever you want as long as noise never exceeds a certain level.

But we will always have to come to these decisions in a democratic way. Simply removing all restrictions tomorrow will lead to cities that are both unplanned and feel undemocratic to the people living there.

Foremost on every New Yorker’s mind right now is transportation—from the subway’s so-called “summer of hell” to the ongoing crisis at Penn Station. The Bloomberg administration had some significant transportation accomplishments, from adding subway cars and new ferries to the enormous transformation of the city’s biking infrastructure with bike lanes and bike share. But you also suffered some of your biggest defeats over transportation, like the effort to institute congestion pricing, and the desperately needed Hudson Gateway tunnel, which Chris Christie notoriously killed. What does NYC need to do now to address its deepening transportation crisis?

Transportation was a huge focus for us. It was frustrating because New York City does not control the MTA, and it can’t raises taxes (other than property taxes), including tolls, without the approval of the state legislature. A core part of PlaNYC, our pathbreaking sustainability plan, was a proposal for a $50 billion investment to enhance the mass transit infrastructure in the city. The plan was to be funded in part by a congestion pricing charge, where people would have been charged $8 to travel below 86th Street, as well as separate City and State contributions.

That plan would have not only brought the system up to a state of good repair, but also made dramatic expansions in transit capacity, including new bus routes and enhancements of the subway lines. Needless to say, that plan did not happen. It died at the hands of the corrupt Sheldon Silver, the Speaker of the Assembly in Albany. Ten years later, now that the system is so clearly collapsing around us, some of our ideas are getting raised again. I have every expectation that at some point over the next few years some form of congestion pricing will be adopted because at the end of the day what makes New York City work is the ability for people to get into, out of, and around the city. It’s pathetic that it will take a crisis to make these investments happen. Leadership is about making the tough decisions before there is a crisis.

You describe a couple of your interactions with Donald Trump when you were deputy mayor, including one where he repeatedly called you to inform you of the ratings of “The Apprentice” after you denied his proposal to build another luxury high-rise at Columbus Circle. Do your experiences with Trump the real estate developer give you any insight into Trump as America’s President?

I will admit that my relationship with our 45th President was generally productive and constructive. But based on the interactions that I describe in the book, what we are experiencing now isn’t surprising. I always say, people don’t change much. That’s certainly the case with our President.

Why would someone I really hadn’t talked to for a year and a half call me out of the blue to tell me, three or four weeks in a row, the ratings of The Apprentice? Or why would he send back to me a scanned version of the farewell e-mail I sent out when I left City Hall saying “Great Job!,” but then correct a minor typo in it. So I saw the seeds of his inexplicably needing to boast of his achievements, always appear to be right, and one-up everyone (while maybe engaging in some anticipatory bullying). They were just small examples of what we are experiencing magnified on the biggest stage in the world.

You devote an entire chapter, plus the epilogue, to explaining Mike Bloomberg’s leadership style and the key things that made the Bloomberg administration work. I am sure mayors, urban leaders, and our readers would like to know more about them.

Bloomberg’s leadership style was unique. He told me when I first interviewed for the job that his style was to pick great people, give them the space and support to let them do their jobs. He lived up to that every step along the way.

He gave us the room to be creative, and to be empowered. That’s part of why people stayed as long as they did. Many people stayed in the Bloomberg administration for the full 12 years. I stayed for six years, which was the longest anybody had been in my position. People believed they would get things done, often of historical significance, and he was going to be there to support them. That was something that made people feel incredibly energized.

I tell the story in the book of when one my major initiatives, the West Side stadium, was becoming a massive political liability for him just as he was gearing up to run for reelection. I went to him and said to him that if the cost of winning the stadium battle (and the Olympic bid that was closely associated with it) was him losing the mayoral race, then maybe we should drop it. It wasn’t worth it. He responded with an anger that I hadn’t experienced from him in our 13 years working together. “We got into this together. It’s the right thing for New York. We’re going to see it to the end!” he retorted. And when it ultimately went down in defeat, the only thing he asked was, “What’s Plan B?” At the time I didn’t have one, but he trusted I would come up with one.

In my entire time at City Hall, I can not recall a single discussion with him about the impact of an initiative or an effort on his reelection prospects. I think that’s an extraordinary thing for an elected official. I think it was why he was so popular (and why today polls about his tenure as mayor still show 70% approval). He was entirely without guile—he said what he was going to do and then he did it. Of course, being very competent helped too. But the main lesson of the Bloomberg mayoralty is that people support a politician who they trust, even if they don’t always agree with him or her.

You now lead a new company, backed by one of the largest tech companies in the world, Google’s parent, Alphabet, focusing on new models of urban development. Can you tell us more about that and how your experience in NYC with the Bloomberg administration shapes this new chapter of your work?

For me, what I am doing now is the culmination of the last two phases of my career. First in the Bloomberg administration, thinking about what makes cities tick, and then I had the experience of running the largest tech company in New York City, Bloomberg LP. It was the combination of these two experiences that led me to begin to appreciate that we are entering what I like to call the fourth technology revolution for cities. Digital technologies, like ubiquitous connectivity, sensing, social networks, advancing computing power which enables machine learning and artificial intelligence, and new design and fabrication technologies, have the capacity to become every bit as impactful on urban environments—across every dimension of urban life—as the three previous revolutions, the steam engine, the electric grid and the automobile, were.

Today at Sidewalk Labs we are exploring what emerging technologies will mean for cities. We want to do that by building a large scale district where we can pioneer—on an integrated basis—many of the innovations that are or are becoming possible. We believe that we can demonstrate that cities can become much more sustainable, more affordable, and more enjoyable. That we can erase some of the bad friction I talked about but still keep the good friction that makes us love our cities. Cities are facing real challenges today, but there are also some very exciting solutions we hope to play a critical role in helping to show are possible.