What impact a subway map’s design

A new paper underscores how the design of a subway map can impact passengers' travel decisions.

New York City’s subway map has a tortured existence. As I’ve written many times over the past four and a half years, the map is not quite schematic and not quite geographically accurate, and thus, it serves only as a loose proxy for navigation throughout the city. According to a new study, that could lead to warped perceptions about New York.

In a paper entitled “Mind the map! The impact of transit maps on path choice in public transit,” NYU graduate professor Zhan Guo explores how cartographical distortions can impact people’s relationships with the city writ large. The Transportationist highlights the paper’s conclusion (and a working paper edition is available online). It reads, in part:

The case study on the London Underground confirms that a schematic transit map indeed affects passengers’ path choices. Moreover, the map effect is almost two times more influential than the actual travel time. In other words, underground passengers trust the tube map (two times) more than their own travel experience with the system. The map effect decreases when passengers become more familiar with the system but is still greater than the effect of the actual experience, even for passengers who use the underground 5 days or more per week.

The paper also shows that the codification of transfer connections is also important. Different codification can make a transfer look more or less convenient on a transit map than in reality, which will either decrease or increase the perceived transfer inconvenience for the corresponding stations. This paper observes both situations in the underground case study and quantifies this codification effect, in terms of the number of attracted or precluded transfers, for four major transfer stations: Baker St., Bank/Monument, Victoria, and Oxford Circus.

Of course, these results are only based on the London Underground, a unique case in many aspects. Few transit maps enjoy such public popularity as the tube map in London. Many transit maps include prominent geographical features, which dilute the map effect. Other systems have different past or present versions of their transit map, which precludes a lasting and stable map effect. Many metropolitan regions possess an easier-to-comprehend urban form than London, which could weaken the role of a transit map in the formation of a cognitive map. The subway map effect in New York City is probably different from that in London. Therefore, readers should be cautious about making generalizations.

In spite of the last sentence in the excerpt above. Guo ponders how maps can impact transit operations and planning. A map, he says, “might unintentionally shift more passengers to a congested segment in the network and thus form a bottleneck” and a modification of a map could “change passenger behavior and mitigate platform and train crowding.” It’s the ultimate in human behavioral manipulation underground.

Over at Greater Greater Washington, David Alpert explored how applying Guo’s findings could impact the DC map. The changes, he notes, are not necessarily positive ones. A redesigned DC map would better show various landmarks in relationship with each other — Union Station’s proximity to the Capitol is one example — but it doesn’t necessarily improve overall system use.

“This is less useful in many ways than the classic map,” Alpert writes. “Most riders travel to and from stations in the core, and tourists or other riders unfamiliar with the system are most likely of all to do so. This map gives little space to that area and leaves large amounts of empty space at the edges.”

In New York, our map suffers from this problem in certain hub areas. It’s tough to tell how far places in Midtown are from the subway, and transfers are often distorted. For instance, the current iteration of the subway map makes no mention of the fact that the Q and N stop at a different platform at Canal St. than the R train does, and the transfer from the Shuttle to the C at Franklin Ave. in Brooklyn in deceptively far.

Ultimately, as Guo writes, “individual passengers and transit agencies should ‘mind the map’ in order to make their best planning decisions.” It is yet another consideration to ponder as the subway map, always a popular topic of conversation and debate, is revised and reevaluated.