‘How do I move more people?’: As Nashville aims for major transit funding, data efforts are already happening to improve trips

While Nashville works to overhaul its transit system through a referendum this November, other efforts to improve WeGo’s efficiency are already in the works.

Abhishek Dubey, an associate professor of computer science, electrical and computer engineering at Vanderbilt University, is leading an effort to make Tennessee’s transit agencies more energy, cost and people-friendly.

Dubey comes to Nashville from New Delhi, a city, he says, that should serve as a warning to Nashville’s transit system. In New Delhi, because of traffic, it can easily take two hours to travel just five miles.

“You don’t want to do that,” Dubey says. “This is the time to do something. If you don’t do it, you can cry 10 years down the line.”

So, Dubey is doing something through an initiative called “Mobility for All.” By partnering with WeGo and CARTA, Chattanooga’s transit agency, a team of researchers collected millions of data points to develop algorithms that can address agencies’ challenges.

During the pandemic, Dubey created a system that could help Nashvillians see how many riders were on a bus. Now, he is developing one to distribute buses more evenly along roads.

Because of traffic patterns, buses can sometimes “bunch” — when two vehicles arrive at a stop around the same time, despite departing at different times — or “gap” — when a bus doesn’t appear at its anticipated time. This distance can either be inefficient for the agency or inconvenient for the rider. So, the algorithm improves the bus schedule to prevent both possible hiccups.

But it’s not easy.

“Nashville is a very dynamic city. Lots and lots of people are moving in. Things are changing,” Dubey says. “So how do you design a schedule that changes rapidly along with people?”

Because Chattanooga is a smaller city, the initiative can go further. There, the team is developing formulas — based on bus types and weather data points — to dictate which bus to use at which time.

Chattanooga operates a mixed bus fleet, meaning that it includes a range of vehicles: electric, hybrid and diesel buses.

Different weather conditions and destinations can all impact a bus’ efficiency.

For example, if a bus is going downtown, the braking system on an electric bus makes it more efficient to use than a diesel bus. In colder weather, diesel buses become preferable to electric buses. When driving up an incline, a hybrid bus is ideal. And, when its windy, electric buses are the most aerodynamic and efficient option.

By analyzing data points, the initiative provided these insights to CARTA. Then, they generated an optimal schedule that would use less fuel and produce fewer greenhouse emissions.

Over 70 trips — and 100 buses in a fleet — researchers showed that around $150,000 could be saved using the new schedule.

The schedule is designed to save energy and also money that can then be put back into the transit system and encourage more people to ride, Dubey says.

“At the end of the day, your roads are a finite resource. So, all of us are effectively asking the same question in transportation research: How do I move more people?” Dubey asks. “The only solution is to put people together into a unit vehicle.”

But, in a place as spread out as Nashville, people are conditioned to use their car. So, not only do Nashvillians need to become accustomed to public transit, the system also needs to be designed to suit the city’s layout.

“Nashville is so big that I don’t think one single strategy works,” Dubey says. “They will have to do different strategies in different places.”

Nashville isn’t alone. According to Dubey, it’s a hurdle faced by the entire southern region. He hopes to eventually expand the program across the state and is in talks with the transit agencies in Memphis and Knoxville.