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Dimitris Papanikolaou: On-Demand Mobility Systems: Lessons from System Analysis and Data Visualization

Dimitris Papanikolaou, Doctoral Candidate Harvard GSD

The early 21st century has witnessed a boom in what is known as on-demand mobility (MoD). Widely perceived as emerging modes of sustainable transport, MoD systems utilize shared vehicle and parking resources allowing citizens to move from point to point on demand while cities to reclaim back urban space. Bike share, the quintessential and most widely adopted MoD model today, mobilizes more than 6M daily trips in 950 cities while its industry nearly doubles biannually. Behind the scenes, about 30 percent of this trip volume is rebalanced each day through an army of trucks, gas, and employees who continuously move bikes from full to empty stations. Rebalancing alone costs more than $3B and 250K tons of CO2 emissions each year, yet half users complain about service availability. In motorized vehicle sharing, this is dramatically worse. No matter technology, the absolute measurement of efficiency cuts down to the value of the least-cost combination of empty trips, vehicles, and parking land required per demanded trip. There is currently no unified theory in any literature that can coherently explain what parameters, and how, drive these three variables in equilibrium, why cities persistently rebalance so much, and why some cities have over a tenfold magnitude performance than others even though the technology and operations they use are commensurate. In this talk I discuss how urban form, land use patterns, and unavoidable sizing and rebalancing decisions define ridership, cost, energy, and thereby limits of MoD systems as a result of a dynamic equilibrium. Using Boston’s bike sharing system as a case and working with interviews, novel data visualization techniques, and a dataset covering over a year of operations, I present a novel system dynamics model that uses as input existing trip data from riders and trucks and allows a user to control size and rebalancing parameters and numerically simulate the dynamic transition of the system. The model and visualizations describe the palindromic vehicle mass exchange between residential and commercial areas and allow planners, researchers, engineers and designers to interactively explore alternative “what-if” scenarios such as: how would ridership in Boston change for a marginal change in the systems size or rebalancing policy? Most importantly, they can be use as tools to build an intuition on the complex behavior and limits of point-to-point MoD systems.

Dimitris is an urban scientist, designer, and engineer, with a background in digital media and computation, and interests in social, behavioral, and learning sciences. His research studies the interrelation of mobility, information, human behavior, the built environment, and economic constraints, through the lenses of complex systems analysis and data visualization. Dimitris has more than eight years of experience in groundbreaking research on urban mobility worldwide. At the MIT Media Lab he co-developed Mobility on Demand (MoD), a vehicle sharing system of electric foldable cars that allows users to make point-to-point trips while minimizing parking space, named by TIME magazine as the best automotive invention of 2007. His research has received distinctions including the $100K Buckminster Fuller Challenge that awards “outstanding visionary projects with the capacity to solve humanity’s most pressing problems”, the $15K Harvard’s Deans’ Design Challenge: Urban Life 2030 that awards “projects that envision order of magnitude improvements to the livability of our cities”, the MIT Transportation program’s showcase award for the best research in Economics, Finance, Policy and Land Use categories; Harvard University’s Fellowship on Energy and Environment, and Harvard Kennedy School’s award on Transportation research. Dimitris has been an adjunct Assistant Professor at the Interactive Telecommunications Program (ITP) of NYU, and has worked at Microsoft Research (Computational User Experiences / Vibe / Lab of Things), at the MIT Media Lab (Smart Cities / Changing Places), and at the MIT Design Computation groups. He teaches frequently courses on urban mobility systems, interactive environments, integrative design, game design, and computational design at NYU, MIT and Harvard. He holds a Doctor of Design from Harvard GSD, an MSc in Media Arts and Sciences from the MIT Media Lab, a SMArchS in Design Computation from MIT’s School of Architecture and Planning, and a Diploma in Architectural Engineering from the National Technical University of Athens.