Pedestrian flags are expensive, and don't do much good, according to the nonprofit advocacy group BikeAthens.

Its most recent newsletter quoted a study of seven intersections in Berkeley, CA: "The use of flags did not seem to have a significant effect on driver behavior." A similar study in Seattle said the flags had "limited effectiveness," and the city canceled the program. Both cities cited frequent flag thefts that cost Berkeley $10,000 and Seattle $17,000 over three years.

Salt Lake City, UT, called its flag program successful, but even there, only 14 percent of pedestrians used the flags. The flags also were coupled with higher fines for drivers who don't yield to pedestrians.

In a story about pedestrian flag programs, The Atlantic blog CityLab concluded, "Expecting people to carry flags so they can cross without getting killed… only increases the sense that being a person on foot is somehow weird or embarrassing. Cities should instead be doing everything they can to advance the radical notion that walking is a perfectly normal thing to do."