These convenient little yellow "markers" were there, I devised, for several reasons. One was traffic control - if you kept to the left you were more than likely OK. These yellow markers were also raised so that a sight-impared person could "feel" along and know where they were. See how the bar goes across the way where the steps start? Another guide for the sight-impared. Pretty clever!

These yellow markers were on every street and in every subway/train station.