Mapping a city's public transit system is, by necessity, an exercise in abstraction. Designers have to balance legibility with detail, clarity with accurate geographic representation.
Boston-based designer Peter Dunn has been thinking about these constraints for the last few years, and he's come up with a couple of new ideas. He's rendered L.A.'s tangle of freeways as a subway system, and mapped the buses along D.C.'s H Street Corridor in the style of London's iconic "spider maps."
Dunn's latest creation, launched for pre-orders today via Kickstarter, maps the public transit systems of the Bay Area based on a useful but deceptively difficult to render metric: how long it takes to get downtown.
"If you look at an ordinary map you can see how far away places are," Dunn explains. "But how far away places are as the crow flies or on the highway is not necessarily the most relevant piece of information. What's more important is how long it takes."
To build his map, Dunn looked at the schedules for BART, Muni, and Caltrain, the three train systems connecting San Francisco, Silicon Valley, and the East Bay. Each system gets its own line and color (that means stations where transfers are possible appear multiple times).
The map helps drive home just how much the time between two stations can differ depending on which way you go.
Take the stop in suburban Millbrae, which shows up on the map three times in the section below. It takes about 35 minutes to get from the Embarcadero to Millbrae on the BART line, in orange, and it's about the same on the local Caltrain (not including time for a transfer). But the Caltrain's express Baby Bullet traverses those 16 miles ten minutes faster. And, for comparison, traveling that direction on the local MUNI system for 35 minutes gets you less than half that distance, just to the Le Conte station in the city's Bayview neighborhood.
The time-scale map highlights the different advantages that the three transit systems offer the Bay Area. Muni offers coverage within the city of San Francisco, BART brought parts of the East Bay significantly closer to downtown than even some areas within the city, and the express Caltrain does the same for the Silicon Valley cities along the Peninsula.
Dunn, who has completed similar projects for the D.C. metro and Boston's T and Commuter Rail, says these time-scale maps help us think about how much time we spend commuting, and what we kinds of places we can reach in a given amount of time. "The old Muni Metro system that's plodding along on the street and stopping every two blocks means many of these neighborhoods in San Francisco are much farther away in commuting time than some of these suburban places," Dunn says. "People understand that intuitively, but they don't always get to see it."