Private: Take another road

Next time there’s an attack or blackout in these parts, you might not want to take the Brooklyn Bridge. Evidently its stability is in question and is likely to become more uncertain if future events prompt masses of humanity to walk across it again:

…the New York City Department of Transportation acknowledged that it received numerous reports from concerned residents [who crossed the Brooklyn Bridge during the blackout trek]. On the bridge, pedestrians reported feeling seasick, having to weave as they walked, and hearing noises ranging from creaking to grinding….

Contrary to logic, pedestrian traffic is actually heavier than vehicular traffic. Pack people into the same square footage of a car or SUV, and the humans weigh more than the vehicle.

What’s more, pedestrian movement interacts with a bridge—vibrating it, in the words of several engineers—in a much more chaotic and little understood way. While cars and trucks move their weight in a smooth, uniform manner, pedestrians constantly shift weight from side to side and strike the bridge in an up-and-down motion. Witnesses observed the bridge reacting to both types of pedestrian stress on the day of the blackout.

For the record, when I walk home, I take the Williamsburg Bridge. It leads right into, um, Williamsburg, and is the northernmost bridge on this map.