When the weather is not too hot for it, I walk to or from work about three days a week. The distance is a little less than three miles by the shortest route, which follows 16th St. NW and requires about an hour. Long ago, I learned the timing of the lights on U through P Streets. At an easy walk, the pedestrian who begins to cross U St. just as the light changes to green will arrive at the next five lights just as they turn. It may be possible to do the same at a very brisk walk, but I haven't tried it.
There have been times that I was in the middle of a block coming toward the next light and thought by the number of seconds shown on the pedestrian signal that I could hurry and cross. This has never worked, though, and eventually I noticed that the light will, at least some of the time, jump ten seconds suddenly. Today I watched one light, probably at S St., as the seconds display went from 16 to 6. I wonder idly whether the count ever runs down all the way by seconds, or whether the jump is constant on these lights. I think that I have seen the same behavior at one of the L St. intersections, a bit southwest of these.