I will try to get video of pedestrians crossing Pennsylvania Ave to see how effective they are. When you are coming westbound on Pennsylvania Ave, you don't even know there is a crosswalk at Fort Davis St until you are almost at the crosswalk because of the topography. I'll also try to get video driving westbound to see how far back motorist can see them.
I don't know the whats, whys, hows, and whos of where they came from, but I'll take this opportunity to thank the sign fairies at DDOT. It's nice to know we have friends in DDOT that are paying attention to the issues in our neighborhood.
Effectiveness of in-road Pedestrian Signs
The engineer in me was interested to know the effectiveness of these type of pedestrian safety devices at unsignalized intersections (i.e. no traffic light). I found a study from 2000 issued by the Federal Highway Administration Turner-Fairbanks Highway Research Center. The study found that motorists were more likely to yield to pedestrians after the signs were placed in the roadway. They were most effective on two-lanes, low-speed roads.
I also found a study by the Transportation Research Board issued in 2006 that confirmed the findings of the other study.