At the start of the Pedflag program in 1995 we began with orange flags. In 2006, we hired a consultant to study how we could get more people to use flags. We used social marketing techniques to improve the system. The study involved interviewing people who did and did not use flags to understand why people were not using flags. The system was then redesigned using marketing principles to address these barriers.
According to the consultant’s report(PDF, 3MB), one barrier was that pedestrians didn't know what the flag was for. The countermeasure for this was a new flag style which echoes the pedestrian warning sign in color and symbol. Another barrier to usage was that sometimes there were not enough flags available. This resulted in the redesigned holder which can hold more flags.