As early as February 18, 2006 (Wednesday), ComfortDelgro began fitting its CityCab taxi unit of about 5,000 taxis, with rooftop EDS (Electronic Display System). The regular taxi fleet consisits of Toyota Crown and Nissan Cedric.
ComfortDelgro's other Taxi units, Comfort and Yellow Top Can, already has the EDS on all of the taxi a few years ago.
The EDS removes the hassle of cabbies putting up the orange NOT FOR HIRE sign. It is also clearer and sharper. However, cabbies who does not wish to pick up customers at any time may switch the EDS to ""BUSY"" . This will prevent them from accepting any taxi bookings. The ""ON CALL"" sign will only be activated automatically 30 minutes before the appointment (if the cabby has a booking).
A famous reason for the EDS is that many customers claimed that cabbies refuse to pick up customers for "no reason" such as near midnight, or simply cruising around waiting/ hoping for a booking, by just puting up the plastic "ON CALL" sign.
http://i7.photobucket.com/albums/y297/105090/CityCab/CityCabEDS.jpgold TAXI sign.. something in history now..

More photos will be attached later.