The mid-block crosswalk at a flashing-yellow pedestrian signal does work. A pedestrian presses the button, the overhead lights flash yellow, drivers slow or stop, and the pedestrian crosses. The system responds visibly, with no covert work happening underneath. The button does what it claims. But the same system also fails, often, in ways that have nothing to do with the button itself and everything to do with what is wired several layers behind it. A reader pointed out that drivers in his city tend to keep rolling through the flashing yellow if the pedestrian is still on the curb, and only stop once the pedestrian commits to the street. The same reader noted that drivers in his town do not give flashing yellow signals the obedience they give to red lights. Here in Jersey City the same mid-block button gets a more reliable yield because the lights are tied to traffic enforcement cameras, and drivers know that yield failures can become citations they actually have to pay. The button works because what is wired behind it works.

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