I walked back a slightly different way (still using 35th Street, but turning down M to stop for lunch before taking the metro from Foggy Bottom). I often find this frustrating since M Street often has a lot of very slow moving tourists, inevitably walking 3 or 4 abreast. I have a theory that hospitals release patients onto M Street right after hip replacement surgery as a form of physical therapy. But it wasn't bad today at all, so maybe they don't do hip replacements on Monday mornings.
Anyway, later in the day, I was reading the Dr. Gridlock chat on the Washington Post's website and one of the subjects was pedestrian safety. My experience with this walk (and walking around the city on Saturday) reminded me of a key point that the planners who are lamenting pedestrian death seem to have missed.
Namely, the lights are designed to favor drivers and bear no relationship to how long it might take a pedestrian to cross a street. Again and again, I cross little one-lane streets where the count-down timer indicates that you have 60 seconds (or more) to cross. And then you come to 6 lane streets where they give you a mere 20 seconds. This has got to be a significant hazard for the mobility-impaired.
Perhaps the best approach is the one in my neighborhood. The light at our corner (which leads to the metro station) gives you only about 15 seconds normally. But, if you push the pedestrian button, that increases to roughly 40 seconds.