2020 40 Under 40: Simon J. Berrebi, Ph.D.

Aug. 18, 2020
Simon J. Berrebi, Ph.D., Postdoctoral Researcher, Georgia Tech
  • One word to describe yourself: TransitNerd
  • Alma Mater: McGill and Georgia Tech
  • Favorite hobby(s): Cooking
  • Fun fact about yourself: I learned how to cook from my French mother and Tunisian grandmother.
  • Favorite station or stop that you have ever visited or frequent (and why): My bus stop has a MARTA Army sign with a map, schedule and QR code for real-time info.
  • Favorite route you have ever ridden or frequent (and why): Metro Line 6 in Paris is full of sleepy commuters in the early morning. But when the train suddenly jets out of the ground to traverse the river through the Bir Hakim bridge, an orange sunrise on the Eiffel Tower electrifies the entire wagon for an instant.

In an industry in need of innovative practitioners, Simon Berrebi has emerged as a rising star. As a researcher, a data scientist and an activist, Berrebi has made profound advancements to the field of public transportation, especially bus transit, equity activism and research.

As a Ph.D. student at Georgia Tech, Berrebi invented, developed and implemented a real-time dispatching algorithm to minimize bus bunching by adapting headways to the current operating conditions rather than relying on schedules.

While completing his studies, Berrebi founded the MARTA Army, which has become the main transit advocacy organization in the Atlanta region. The organization crowd-funded trash cans for 100 MARTA bus stops and the MARTA Army partnered with the authority and the local ATU to recognize exceptional bus drivers at an annual gala.

Berrebi has also helped transit agencies understand the underlying causes of ridership decline through research funded by the Transit Cooperative Research Program. Berrebi used big data generated by automated passenger counters to identify some causes for ridership decline, but also developed actionable strategies to reverse the trend. The work was covered in a New York Times profile published in March 2020.

Berrebi’s work has been put to practical use, such as in Minneapolis, Minn., where Metro Transit selected software Berrebi developed in partnership with Cambridge Systematics to predict bus arrival time. In conjunction with Ireland-based developer, Sean Òg Crudden, Berrebi developed an adaptive algorithm to predict bus arrivals in real-time as part of open-source software TheTransitClock.

“With the advent of inexpensive sensor devices aboard buses and trains, data is becoming increasingly available and accurate. The data can help us gain a better understanding of the underlying dynamics at play in our cities,” said Berrebi.

Berrebi has presented his research at numerous conferences and serves as the research coordinator for the Transportation Research Board’s Bus Transit Committee.

Is there a specific experience that led you to where you are today?

Growing up in Paris, France, I started riding buses and trains at a young age. I never thought I would become a TransitNerd one day. Riding transit felt natural, so I took it for granted. After working in supply-chain consulting post-college I was planning to do a Ph.D. in math when I found out about the fascinating work of Dr. Kari Watkins. So, you solve interesting problems AND make a tangible impact in the real word? I have never looked back since.

Best advice/tip/best practice to share from your area of expertise?

With the advent of inexpensive sensor devices aboard buses and trains, data is becoming increasingly available and accurate. The data can help us gain a better understanding of the underlying dynamics at play in our cities. Based on this understanding, we can invent transit systems that provide more effective, inclusive and reliable service. But using data to answer biased questions leads to biased answers. Data analytics is only useful when combined with a critical perspective on how cities operate and the capacity to challenge assumptions.

Why do you like being a part of the public transit industry?

Public transit is the silver bullet in the fight against climate change. Not only does it curb GHG emissions in transportation, which contributes more to climate change than any other sector of the economy, but also protects cities from the catastrophes that arise because of climate change. This year’s pandemic shows that the environmental and social impact of our actions can only be ignored for so long before they erupt into our lives with greater magnitude. Hopefully, we will pivot out of this moment with a collective reckoning that the car-centric approach to building cities has reached the end of the road.