Bingqing Liu and the Transportation Revolution

Bingqing Liu

Student, NYU

"Transportation," says Bingqing Liu, "can be revolutionary." For Liu, the rapidly changing nature of transportation systems is its biggest draw -- as early as high school, she was fascinated by how quickly transportation technology was evolving.

Few other fields are poised to make such rapid, revolutionary changes in so near a future. Says Liu, “Different types of new transportation technologies and companies are emerging constantly, leading to faster and easier traveling.”
At least, in theory. Liu is fascinated not only by the technology itself, but by its application in society – how do these advancements make life better, or easier? How does advancement respond to need?
The trick is: sometimes it doesn’t. “The famous Braess Praradox shows that sometimes building more roads can lead to more congestion,” Liu explains; hence the technological revolution of transportation might need a more systematic view, which has been the impetus behind the research Liu has been working on in her studies. She wants to understand how transportation modes work together, and their impacts on one another and on the people who use them.

“I’ve worked a lot on network modeling, especially under a multimodal setting, considering more sustainable and equitable modes,” she says. She’s worked on a project that looks into quantifying network connectivity in terms of biking as a means of accessing public transit, considering network structure, transit availability, bike infrastructure, and so on. She helped developed a publicly-available electric vehicle charging infrastructure evaluation tool that considers M/D/C queues at charging stations, and tested it on NYC city-owned electric fleet.

With Mobility-on-Demand (MOD) emerging as an important part of multimodal transportation systems, Liu has been part of a stochastic user equilibrium model which considers a concept named congestible capacities, which refers to a network characteristic of MOD that the link capacities keeps changing with the flows. And she’s worked on a day-to-day adjustment model for microtransit simulation collaborating with VIA.

After working on different modes separately, Liu seeks to model the market consists of multiple users, operators, and modes, which leads to her current focus

What's your favorite way to get around the city?
I always find myself traveling around the city in a multimodal way. I may cycle to somewhere and then take the subway, or rideshare and walk. That's one of the reasons why I'm looking into Mobiltiy-as-a-Service in my work.

Bingqing Liu
on Mobility-as-a-Service (MaaS). She is developing an algorithm which is able to find optimal subsidy plans and corresponding network flows in a market with multiple modes and operators for the users, even if there are no natural stable matchings between the users and operators. 
In addition, perhaps unsurprisingly given Liu’s interest in the way that transportation systems impact the people who use them, is about equity in terms of data. “The problem is that, due to small sample sizes, the census data reliability of minority groups is generally lower than the majority groups,” Liu explains. Her solution is a zoning algorithm to group small geographic units into optimized, large zones to improve the reliability of minority data.

In other words, using the grouped, more reliable data to better understand where are these underrepresented people – and how they’re being served by the current transportation systems.

It’s work that harkens back to the problem of stagnation in daily travel time, a problem which folks today share with folks a century ago. What is the best way to get where we’re going? How can the systems be better managed? How can we provide better mobility services to everyone in our society?

“However, despite the great changes in transportation technologies, research showed that people’s travel time remains close to a fixed value for centuries. This shows that traveling is an eternal need of human beings,” Liu says,  “which is really fascinating to me. This field will never become outdated.”

Perhaps her earlier note – “transportation can be revolutionary” – is less a call for a single shift in transportation systems, but rather a nod toward the ever-evolving nature of it. The revolution in transportation systems is happening all the time, and always will. And Liu hopes to be a part of that: “I hope to become a researcher that keeps digging into the future of transportation, no matter in industry or academia.”

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