TAMPADavid Dixon and Jeff Speck are two of the best urban planners in the business.That's why Jeff Vinik hired them.The Tampa Bay Lightning owner is planning a $1 billion transformation of the downtown waterfront. He wants to spend the next decade turning 40 acres of empty land and existing development into a livable space that will appeal to two important demographics: millennials and empty nesters.That's the speciality of "new urbanists" like Dixon and Speck. They're leading practitioners of "new urbanism," the movement to make cities more appealing and accommodating to human activity in order to generate economic activity.They do that by creating urban spaces that will better attract housing, jobs and people by making cities more hospitable to pedestrians and bikes, and far less dependent on automobiles. Dixon and Speck will spend the next four months designing those kinds of urban public spaces for Vinik's project.Dixon, 67, was named to Residential Architect magazine's hall of fame in 2012. He is a senior principal and urban design group leader at Stantec, an international engineering firm.Speck, 51, runs his own Washington, D.C., design agency, Speck & Associates LLC. He's become one of new urbanism's most forceful voices for reshaping cities, but also as an antidote to the ills of suburban sprawl.Speck is also the author of the influential new urbanist book Walkable City: How Downtown Can Save America, One Step at a Time, which has become required reading for Vinik's team.Both spoke to the media this month about how they plan to impact Vinik's plan. Here's more of what they had to say about their goal of creating a walkable Tampa and how they hope to achieve thatYour job is to design the ground floor — the sidewalks, public spaces, benches, foliage, store fronts and other pedestrian amenities — for Vinik's project. What does that entail?Jeff Speck: We need to give the architects that will be (designing) the individual buildings in the project a firm understanding of what their urban obligations are. Where they put their buildings and how those buildings meet the street.The way we like to say it is we're trying to create documentation that will ensure that the construction of the private realm creates an ideal public realm, that everything that's done as a private building makes building the public spaces a better experience.David Dixon: When you build a new urban district every building has to help each other create that public realm.In December, when Vinik finally made his redevelopment plans public, he said he was putting together a "vision plan." Does this mean the vision thing is over?DD: It doesn't mean that visioning has ended. It means that visioning has ended at that level of detail. . . .You can deliver each parcel to a developer or user, and they should know how much retail space to put in and where. How wide do the sidewalks need so there's room to sit outside under an umbrella and dine? These may sound like details but they're the ones that make or break a really great place.Dixon talked about how Vinik's urban renovation project would be designed to draw young, educated workers and residents to downtown Tampa.DD: Every city in America is competing as a place where bright young folks with college educations . . . will want to come over and work because our future is our knowledge industries.What Jeff Vinik and the Lightning are doing is really probably building Tampa's best example of that. There's a lot of opportunity and a lot of responsibility, and I think one reason we're here is because Jeff wants to make sure that he pulls every bit of opportunity out of this place.He doesn't just want a great district, a great setting for the Lightning to play, a great place to hang out on Thursday night, but a really great place to make Tampa a more competitive city and region.So how do you go about designing a "great district" that will also be pedestrian-friendly and encourage people to walk?JS: We'll be designing the public infrastructure. The trees. The lighting. The benches. A simple example is retail. Retail only works (to encourage walking) when it's continuous. You can't have retail and then an office and then retail and then somebody's house.The vision plan envisioned certain retail locations, but it didn't lay out the rules that if you're on the north side of street X, you have to be retail. So our plan will have rules in place like that.Even down to the square footage that a store can use?JS: I don't think it will say what every square footage needs to be. But for example, if you're going to interrupt retail with something else, like a lobby, the lobby can only be so long or else people won't shop across from it.DD: Exactly. There are all sorts of rules of thumb that may sound like generalities, but they tend to really work.People may say they walk long distances, but they're probably not going to walk more than five minutes — that's a quarter of a mile, that's a couple of blocks — without a really compelling destination.So we have to make sure that every 1,000 feet there's a compelling destination. . . . These details have to come to life if we want the district to come to life.Dixon then talked about designing a public realm that must appeal to more than just millennials. It must also draw families, teenagers, young children and retirees to Vinik's project:DD: This is meant to be a family district. So it's great to say come and eat and drink, but there's a whole bunch of us who aren't 18 yet.If we don't build compelling places for teenagers and younger than that, then this isn't really a place for everybody from every walk of life.So we're not only looking at the details. As you look at the public realm, are all the places there to appeal to the different kinds of people who make up Tampa.One of the goals of Vinik's redevelopment project has been to focus on health and wellness. How does urban design promote health?DD: It's about healthy buildings. There's a whole lot of research out there that says the ways we build buildings today — still with all we know — still produces some lousy air quality that affects our performance, and there's a whole bunch of new data that talks about how many billions of dollars a month of lost productivity that America experiences because of poor air quality.But that being said the thing in our lives that correlates most directly with our health is walking. We're here to create a walkable district. If this is going to be a healthy district, then people will walk two blocks further to the arena because they'll walk by a great main street that's fun.JS: But ultimately making it more walkable isn't just improving the experience of walking in it. . . . People tend to forget that the single greatest determinant of our health is, for a number of reasons, not just walking, but being freed from the requirement to drive.Between the lack of activity that driving causes us to have and the very real risk to our bones, I have to say that Tampa is one of the most dangerous cities in America in terms of deaths of both pedestrians and drivers because it has been designed around the car for so long.Freeing (residents) from the burden of mandatory driving is the healthiest thing they could do.It would be hard to find a city more car-centric than Tampa. How can urban design possibly free residents from the burdens of driving?JS: There's only one way to stop that problem, and that's neighborhood by neighborhood.It's dangerous because the streets look and feel like they were designed for going at high speed because they are designed for going at high speed.So one of our charges is to work with the city and engender the cooperation of the city in creating street configurations that encourage people to drive the posted speed limit.Because right now the speed limit says X and the road is telling you 2X. That's been a problem that's not unique to Tampa. That's been a problem all over America.DD: It's the road that sets the speed. Not the speed limit.Contact Jamal Thalji at [email protected] or (813) 226-3404. Follow @jthalji.