How About A Green Light, Sir?

RFID in Japan: A recent article on Mainichi Shimbun discusses uses of near-future technologies including RFID. It argues that RFID tags can enhance the safety of the elderly and the handicapped at pedestrian crossings. The scenario goes as follows:
The elderly and the handicapped receive RFID tags whose information is registered in a database. They wear the tags on their chests when they go out. When they come close to a traffic light that is equipped with a sensor device, the computer that controls the light can recognize the RFID tags, change its state to a green light and make sure that it doesn’t change until they finish crossing a street. Such a system may reduce certain kinds of traffic accidents.
Sounds to me like a good idea, but will this scheme actually work? I know it doesn’t if everyone has such RFID tags…
How About A Green Light, Sir? [RFID in Japan]