Today, more than half of the world’s people live in urban areas, the United Nations says, and by 2050 two-thirds of us will. As cities become more numerous, bigger, and more complex, the study of these agglomerations is also booming. At NYU Abu Dhabi, researchers from many disciplines are working together to understand and improve the complex and interrelated networks that make up urban life.

Technology has already changed cities in unpredictable ways, says Pablo Hernandez-Lagos, assistant professor of economics. “For example, nobody could have predicted that sewage systems would allow us to increase the density of cities by such a big margin. And then elevators increased population density, so you can have artists living right next to tycoons and right next to workers. That cross-fertilization spawns new ideas.”

And new technologies just keep on coming. Saif Jabari, assistant professor of civil and urban engineering, says the switch to autonomous vehicles may change daily life every bit as much as the shift from television to internet has done. In both cases “all of a sudden there’s two-way communication” and new possibilities blossom. Very soon, “cars will be able to share information with roadside devices; we’ll have cheaper devices, we’ll get a lot more bang for our buck.”

Technological change of this kind also brings exciting new challenges for engineers, adds Jabari’s colleague Monica Menendez, associate professor of civil and urban engineering. “If autonomous vehicles increase the number of kilometers traveled, the system could become more congested. There will be some advantages in monitoring, but traffic as a whole might wind up much worse.”

Etienne Wasmer, professor of economics, has a suggestion there: Changed work habits could help. People do not need to be in the workplace five days a week. If everyone worked from home just one day a week, he says, “that would reduce congestion drastically.” But change of that kind “takes time, maybe generations.”

Major transformations, in traffic or any other field, demand political will, which can be paralyzed by complexity.

Tarek Abdoun, global professor of civil engineering, studies the problems cities can face from earthquakes, hurricanes, and other risks. “Big data” is useful in many ways, he observes, but “in decision-making, having too much data that you don’t know what to do with is as bad as not having any data. Handling big data is a big issue now. A lot of people who make decisions, if they’re overwhelmed with information, basically ignore it.”

Wasmer adds that when he was consulted about plans to expand the Paris Métro (subway), “they asked me for simple models” but often complex problems do not permit uncomplicated solutions. “It’s hard for us to provide the simplicity they ask for. That’s a big challenge.”

Menendez says one way for researchers to address this issue is to involve decision-makers early in the process, “to challenge our thinking and our solutions and to give us feedback on what’s useful and what’s not.” Doing that, she says, would “increase the likelihood of adopting what academic experts suggest.”

Increasingly, the challenge of managing modern cities demands interdisciplinary research.

Abdoun says that’s because teamwork is required to “take whatever the engineering data tells us, and convert it to decision-making tools so stakeholders and owners can know what to do with it.” If he’s assessing flood risks to a city’s infrastructure, for example, he says, “it’s not just a structural engineer working on it. Social science gets into it, human factors, financial …” And then all the findings, from different perspectives, must be merged into “one simple frame of decision-making.” That’s why multidisciplinary cooperation is booming in urban studies. “Research is becoming broader,” Abdoun says.

That’s true for individuals as well as for group research. Economist Hernandez-Lagos sounds more like a social psychologist when he cites a keystone of his work: Cities intensify human interaction, and “the most important feature of … human interaction in general is that our decisions about whether we’re going to collaborate with others depend on what we believe the other people are going to do.”

That concept, familiar to many undergraduates as the prisoner’s dilemma game, is a foundation block of urban studies, and things are becoming remarkably elaborate in our high-tech age. “Today,” Menendez says, “we don’t understand even half of the complexity around cities. If we were to electrify a whole vehicle fleet, for example, what effects would that have on the energy grid?”

Wasmer’s work has focused on identifying the factors that encourage the expansion of urban agglomerations, and those that do the opposite. Not all natural brakes on growth are as obvious as a rising price for land, he says. “We never know which one will strike first. It can be pollution, or traffic, or even a shortage of sand and cement.”

The bigger the city, the more it can be at risk.

Then there’s security, an urban problem since the days when cities had walls. Safety has new urgency in the era of climate change and high-impact terrorism. Increasing risk is a natural concomitant of urban expansion, security expert Abdoun observes. “Ancient cities usually developed in the best areas to populate, near rivers, with good land. But as populations increased, they started getting into areas with engineering challenges.”

He cites New Orleans, in the US: The oldest part of the city, now called the French Quarter, was built on high ground. “But as they expanded, they went to swamp land below the water level.” People there are still suffering the consequences.

Or consider Dubai. “The city is flourishing, and so to expand they started reclaiming land from the Gulf,” Abdoun says, referring to the Palm Jumeirah and similar projects. “This kind of land is … known to be at hazard” in earthquakes, for example.

Despite all the problems, NYU Abu Dhabi scholars are generally optimistic about the world’s urban future. “The city will continue to be attractive as long as humans are adaptive,” says Jabari – and technology makes us more adaptive.

Wasmer is more sweeping: “There is no challenge that cannot be addressed by the human brain.”

And Hernandez-Lagos puts it this way: “We’ve decided to live in densely populated areas where human complexity prevails. And we like that. I don’t see any way in which we are going to go back to the countryside.”