My friends at SmartRadio in the island-republic of Singapore are right on the ball. Public service/emergency service preparedness is all set on digital radio there.
From their site, if a litle paraphrased for international reading....
The Singapore Civil Defence Force (SCDF) Public Warning System (PWS) messages now go out on SmartRadio.
During SCDF's monthly testing of the PWS warning siren, a text message is also transmitted simultaneously on SmartRadio's Dynamic Segment Label (DLS) service and broadcast island-wide. DLS service enables SCDF to disseminate PWS related and other messages to all DAB radios when the need arises.
DLS, one of SmartRadio data services, is a scrolling text message that appears across the LCD screen that is available on all DAB radios. Besides transmitting Singapore Civil Defence Force PWS messages, it also carries many useful infos like synchronized song titles & artist name, traffic situations, weather conditions, ads & promos, etc. Because of its free-to-air broadcast nature, messages can be reliably delivered as it is not subjected to any network bottleneck's condition.
It is worthwhile noting that Singapore seems to be well ahead of Hong Kong its friendly rival when it comes to digital audio broadcasting.
Check out DAB in Singapore at: http://www.smartradio.com.sg