In public buses of the old days, there were a number of “Push Once” buttons placed along the length of the interiors.
Apparently, passengers were “warned” to push or press any of these buttons only once, to tell the driver that they wanted to disembark. And “dire consequences” awaited those who disregarded the warning.
But as these buttons were spaced out at quite big intervals, sometimes it was hard to reach anyone of them, especially when the buses were jam-packed with passengers.
Thus at a later time, newer buses with fitted with a kind of continuous “bell strip” that ran the whole length of the interior, on both sides. These were usually mounted above the window frames. With these strips, it meant that the bell could be activated by pressing anywhere along the central rubberized zone.
But the high placement was a problem.