Thickness of lines is logarithmic because otherwise the huge numbers of people on the blocks immediately adjacent to the downtown stations are about all you can see. Shortest-path routing along TIGER (2010) roadways, which gives at least some kind of approximation to reality, even if it thinks people can walk on the demolished Transbay Terminal loop. Diagonals are especially suspect. BART passenger trip origins from the 2008 Station Profile Study, snapped to the nearest street corner.