Our recent launch in South Boston was the first neighborhood expansion of Bridj since beginning service to Allston residents in early July, and we’re happy to announce that it’s been a resounding success. Though we knew there was great demand and potential for Bridj service in Southie, we wanted to launch a route that would demonstrate the power of our flexible transit system. So, we decided to give commuters direct input into which route to introduce. While voting on one of our two proposed routes, Southie riders also had the option of providing their home and work locations. This helped us not only to launch a customized, hybrid route but also to choose the very best pick-up location. 

Our route-planning algorithm relies on a mix of publicly available sources, anonymous social media data, a number of proprietary data sources, and a liberal dose of our secret sauce, as well as your votes. We aggregated your work locations to create an entirely new hybrid route running from Southie to Seaport, Downtown, and Longwood. There were very few user-generated requests for a Charles/MGH stop in the West End, which we originally thought would be more popular than Longwood. We also took a careful look at the home locations provided to choose the optimal Bridj pick-up location, thereby making commutes to work easier, quicker, and much more comfortable.

Peter Andersen is an operations associate at Bridj and is one of many team members who helps plan routes.

Peter Andersen is an operations associate at Bridj and is one of many team members who helps plan routes.

This challenge of choosing the best drop-off stop location is an applied example of what is called the facility location problem. The goal is to predict the optimal location of a facility, given the constraint of minimizing the sum of travel distances to a set of point destinations. Once we had a general idea of which routes to offer, we clustered work addresses to minimize walk times from each hypothetical stop. We also faced the additional constraint of minimizing total drive time on a Bridj shuttle, which can be tough given Boston’s, shall we say, unique street layout. There is a lot of academic research detailing how certain algorithms solve these types of problems, and we encourage you to look into the subject of location theory if this sparks your interest.

We are particularly interested in this topic, as it directly relates to our analysis of Southie home locations as well. Here, we are optimizing for a minimum sum of walking distance, and thus a minimum sum of walking time to a future Bridj stop. Our goal is to make the Bridj pick-up location as convenient as possible for the majority of our riders.

Though we had an idea of where rider demand is based on preliminary analysis, we wanted to be as thorough as possible. Given the simplicity of a single stop location and a constrained area of pre-determined demand, we carefully examined several locations (and corresponding walk times) in Southie. We ended up with 442 W Broadway as an optimal pick-up location. Below you can see the average latitude and longitude location of all home Southie addresses. Our Bridj stop falls within this central point and minimizes the total sum of walking time for riders.

The average location of all Southie home addresses.

The average location of all Southie home addresses.

Though we only introduced one pick-up location in Southie, we plan (in the very near future) to introduce multiple pick-up locations. This will expand our service area so that most, if not all, of those who signed up will be able to walk to a Bridj stop and continue on to multiple destination spots in the city. You have helped us create a living, breathing transportation system that has the ability to evolve with the input of real data. We are more than excited to start expanding our service to get you comfortably and directly from where you are to where you need to go. Grab a seat on Bridj from Southie today.


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