A Twitter Data Scientist Hacks San Francisco’s Subway Fares

By Sydney Brownstone : fastcoexist – excerpt

Why pay the full price to your destination on BART, when swapping tickets with a stranger mid-ride would save you both money? Perhaps because it sort of violates the social contract?
When New Yorkers move to the Bay Area, they’re often accused of personality crimes. Being haughty, cagey, and ragey-for-no-reason are just a few. I know this because I was one of them, and when I lived in Berkeley, there was one experience that drew out all of the stereotypes I had in me: Riding on Bay Area Rapid Transit, or BART.
Twitter data scientist Asif Haque has had his BART frustrations, too. Thus, he decided to take a data-driven approach to see if its fares were “fair” or not. In the process, he also devised a system to help riders artificially lower the cost of riding on public transportation by switching cards with fellow passengers in mid-ride.
For those unfamiliar, BART’s swiping and pricing system works like this: A passenger puts money on a paper ticket or plastic Clipper card, swipes through a turnstile at the origin stop, then swipes through another turnstile at the destination. How much you’re charged depends on where you eventually exit, and not necessarily how many stops you travel. (It’s a mileage-based formula, plus certain taxes here and there.) Unlike New York City’s subway system, BART does not charge a flat rate ($2.50) no matter where, or how far, you’re going. It also doesn’t offer weekly or monthly discounts for people who rely on it to get to work.
There’s a lot of math involved, but Haque, a game theorist and computer scientist by training, figured out that some people who switch their tickets or Clipper cards with each other mid-route could cheat BART’s fare calculator. In fact, a public ride-sharing scheme could work for some 13% of BART route pairs. For example, one rider traveling from Millbrae, in south San Francisco, to Embarcadero, in the heart of the city, pays $4.50 for the trip. Someone coming from the opposite same direction, Glen Park, and traveling to Berkeley, pays $4.20. If they switch passes mid-route, Traveler A ends up paying $5.10 (Millbrae to Berkeley) and Traveler B pays $1.20 (Glen Park to Embarcadero), together saving $1.70…

That’s one theoretical conclusion. The other outcome is deeply troubling. In 2013, after fares and parking fees, a little more than 38% of BART’s budget was funded by taxes. If the fare slice of the revenue pie decreases, taxes might end up making up the difference. That’s not decreasing the price of a ride, but simply shifting the cost onto the rest of the tax-paying public. To suggest that private companies jump in and make a profit off of potentially starving a public transportation system is a nightmare scenario–one that could create a massive gulf between functional private systems and crumbling public ones.
But Haque’s paper doesn’t really look at worst case scenarios. Instead, it’s purely focused on mathematical price efficiency. He says that he could apply this same analysis to any city’s public transportation, where efficiency is measured not by how expensive a ride is, or how profitable the transit authority might be, but whether pricing is set up in a way that makes it preferable to cheat. “For systems in which nothing is gained or lost by switching, those are efficient,” he says, citing Caltrain as one such example.
Haque suggests that if this inefficiency is brought to the attention of transit authorities, the less opportunity there would be to exploit it. He tweeted his research at BART to see how the transportation system might respond to the notion of changing its fare structure, but has yet to receive a response.
In the meantime, the likelihood of having private companies scale up Haque’s idea is nearly impossible. Crowds relying on paper and plastic ticket swapping is surely more physical trouble than it’s worth… (more)

This brings up the subject of how much all public transit truly costs relative to the fares charged for the tickets. The taxpaying public pays over half the Muni charges on the fares that pay. They pay 100% for all the free rides the city authorizes.

We take no sides on this issue, but, before you vote to approve more Muni bonds and approve initiatives to charge higher fines, fees, and taxes to support Muni services, find out where the money is spent now. Find out what percent of the MTA budget covers the actual operations and maintenance costs, and where the bulk of the funds go.

Ask the SFMTA, Mayor and supervisors how much SFMTA has spent on TEP plans to reorganize bus routes and cut Muni service. When you attend one of the many TEP meetings ask the MTA staff why the fifty new buses they just purchased can’t be used to increase service? Be sure to comment on the TEP in your neighborhood.