I had to cross the bay this afternoon for a meeting in Oakland, California, and I was all set to tackle the BART card-vending machines with renewed vigor. In San Francisco, like in D.C. (but unlike flat-fee New York), you pay for your subway ride based on its length. This requires you to put a little thought into how much money you should put on your card because the machines only return a low amount of maximum change.

When I entered the Montgomery Street BART/MUNI station, all of the farecard slots were taped over with blue stickers and the electronic turnstiles were open. Signs announced a “Spare the Air Day,” which I later learned was heat-induced—apparently, 84 degrees is really hot for the city.
According to a San Francisco Chronicle article, the free rides were to lure commuters away from their cars onto public transportation to avoid exceeding state and federal smog standards. Although transit officials said the campaign drew “significant numbers of new passengers to some systems,” it didn’t sway enough to avoid tipping the smog scale, likely to 90ppb (parts per billion) of emissions for today; the federal ozone standard maxes-out at 80ppb. Hey, at least they’re tryin’.