The standard white light on the roof of a taxi signifies a standard taxi rate as regulated by Point to Point Transport Commissioner of NSW.
A yellow roof sign signifies that the taxi will price match rideshare X1.0 rate. Simply hail that individual cab, scan on and you will pay the discounted rideshare rate in a cab.
The amber sign indicates a shared taxi ride which is 50% cheaper for 2 passengers, 66% off per passenger for 3 or 75% off per passenger for a 4 person shared ride.
Unlike the bus, there is no queue, and your fare is split automatically between passengers.