You'd Better Run!

Have you ever wondered why it's so difficult to get across the street before the "WALK" signal changes to "DON'T WALK"? Well, check out this excerpt from a nationally-recognized traffic manual:

"An average walking speed of 40-ft/s is appropriate for typical groups of pedestrians. . . .At signalized intersections pedestrian crossings must be assigned an amount of effective green time based on average walking speed."

Now, a speed of 40 feet per second is approximately equivalent to 27.3 miles per hour. Do you run across the street at 27 mph? I didn't think so!

OK, OK, it's an error. It's supposed to say 4 feet per second, and the error has been noted by the publisher. But next time I see a fast signal, I'm going to wonder. . .