Spotlight on Faculty: Chandra Bhat
"Are you playing God?" people have asked Dr. Chandra Bhat. The people who ask this question are referring to his work predicting the activity and travel patterns of city inhabitants. This includes the prediction of if and when individuals in a population get married, to whom they get married, if and when marriages dissolve, where individuals choose to live, if and where they work, whether and when they have children, and when they die. These decisions determine the demographic composition and spatial dispersion of the population in an urban region, which, in turn, says Dr. Bhat, helps predict the complete daily activity-travel patterns of individuals in space and time.
The name of this line of work is Travel Demand Modeling. Dr. Bhat and his graduate students have created a computer simulation program that predicts the demographic, residential, and activity-travel patterns of individuals in urban areas. This prediction system is used to examine the impact of alternative traffic congestion alleviation and air quality improvement strategies (such as traffic congestion pricing, fixed and time-varying tolls, work rescheduling, light rail and commuter rail service, parking policies, and telecommuting), and to plan for the aftermath of extreme events (such as terrorist attacks, earthquakes, and hurricanes).
Using the information he gathers, Dr. Bhat works to find ways to make transportation balanced—to have convenient grocery stores, day-care centers, and other indispensable resources close to where people live and work, and close to such transportation hubs as commuter rail stations. This requires solid land use planning as well as transportation planning. He says: "We do some of the research because people can actually use it—and we also do research because we love it."
One of the wonderful things about this research is the extent to which it is, in a way, intuitive. How many times have we looked at a city of sprawl and criticized it for its loneliness? How will the city’s inhabitants connect and identify with each other? Where can people gather? Where can people walk and bicycle? Through scientific and urban planning methods, Dr. Bhat studies demographics and the built environment (for example, the layout of a city and the nature of the transportation system) impact activity and travel patterns.
Many European cities, as well as the core of San Francisco, have compact geographic footprints, Dr. Bhat says. These cities depend on their public transportation systems. On the other hand, many of the large cities in the United States have spread horizontally, which makes it difficult to pinpoint places where public transportation would be useful for large groups of people. In turn, this requires inhabitants to get from place to place by driving alone.
Dr. Bhat developed an interest in these ideas while he was still in graduate school, which he finished in 1988. What drew him was the interdisciplinary nature of Travel Demand Modeling: it’s combining of mathematics, econometrics, engineering, urban planning, and social science. Because of the wide social relevance of this work, Dr. Bhat notes, "there is no dearth of people knocking on our students’ doors and offering them jobs." His former students go on to study travel patterns in cities all over the world in transportation consulting firms as well as in universities.
As for his own transportation habits, Dr. Bhat says that he tries to be physically active and walks or bicycles when he can to access activities. "Hopefully," he says, "it will rub off on my own children."
By Elisabeth McKetta, March, 2007