This is true, you can find many large metropolitan/city's main police frequencies traffic streamed. Though this is getting to be less common, or less inclusive of all the dispatches being sent. Many police agencies have moved to near 100% digital data transmission sent to the field units via their MDT (Mobile data terminals) more correctly now called MDC (Mobile Digital Computers), but at least in the area of Ca I live in they still call them MDTs. This means of communication has many benefits over verbal radio communication. From what I understand it is being used more and more by all those, who have relied on verbal radio communication for years. The advantage of being able to pair the dispatch with GPS/mapping data would work well for cab or courier companies as well as police and other emergency responders I suppose. One of the main advantageous this form of communication has when dispatching police to the scene of a hot/in progress crime, is that it does not allow the perps to hear the dispatch, and therefor be tipped off that the police are on the way. In this area this advantage is somewhat diminished as the local agencies all choose to still use a verbal radio alert/conformation system that consist of the dispatch transmitting something to the effect of, "K9-2, transmission to your MDT", to which K9-2 would confirm, "K9-2, 10-4, 97" (97 = responding/in route) This verbal communication does not give up any detailed information, but in a small, relatively crime free area/town/city it may be enough to spook a perp who knows there is a good chance this dispatch is being sent for him b/c of timing. That is, if he has just done something that was possibly visible to someone, or has possibly tripped a silent, and 1-3 minutes later hears the alert/conformation of a dispatch, this at a time when there might only be on averaged 1 an hour, he may well play it safe and bolt, or move to safety and observe.
But whether the use of a verbal radio alert/conformation system is used, or everything is done by means of audible alert tones piggy backed on the data stream sent to the field units, once radio communication has been replaced, it has finished the monitoring of police activity by civilians that many ppl seem to enjoy. So get it while you can
