Are the yellow lights in traffic signals briefer than they used to be?

Dear Cecil:

Are the yellow lights on the traffic intersections getting briefer, or am I just getting slower as I inch toward 30? Several times lately I've been nearly run over while crossing the street. I tried watching carefully and found that if the light turned yellow when I was exactly in the middle of the street I could just barely get to the other side. Presumably, then, if it turns yellow just after you've stepped off the curb, you could get yourself killed. Was there a change?

Cecil replies:

Dear C.:

Light sequencing is carefully calculated according to a formula found in the Traffic Engineer’s Handbook, which is accepted as a national standard. The formula takes into account the width of the intersection and the speed of traffic, but not the speed of pedestrians–the yellow light, you see, is for cars, not people. If you’re on foot you’re supposed to be watching the “Walk/Don’t Walk” signals, which do take pedestrians into account: about six feet per second in most neighborhoods, four feet per second in neighborhoods that have predominantly elderly residents.

Send questions to Cecil via cecil@straightdope.com.

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