But once you find a SEPTA bus map, you’ll see that it’s mainly limited to showing you that one route, rather than how that route relates to the larger system. Take this portion of the Route 23 map on the left. It shows where you can connect, but not where those connections go. Imagine if you were at a party and needed to use the restroom, but rather than telling you where it was, the host merely said, “Well, that’s in the southeast corner of the house. This hallways runs east, there are doors that might head south. Good luck!”.

SEPTA’s bus maps—including those on some bus shelters, installed by Center City District—also don’t tell you how often the buses come. Some run so infrequently that riders rely on schedules to tell them when to get to the stop, not unlike regional rail.

But plenty of Philly’s buses run far more frequently—a new bus every 8 or 10 minutes—that passengers use them more like they use subways or trolleys: simply show up at the stop and wait for the next one.

Unlike SEPTA’s rail transit, bus transit gets short shrift on SEPTA’s familiar transit map, which shows all the rail lines, even those that only run one train per hour, but none of the buses.

To Thomson Kao, that bias towards rail made no sense, so he set out to do something. Kao created his own, unofficial, frequent service map.