Quick! It's the fuzz!

Back in the day, a certain estate in Manchester had kids playing on all the roads into it.  I forget the exact deal, but they’d keep a lookout for the police and would be given radios to monitor communications to know who needed alerting to hide their stash.  Police technology has moved on with encrypted radio communications, mobile phones and more unmarked police cars.  Technology for monitoring police activity however hasn’t moved on quite so fast, some does exist but it’s expensive and/or difficult and/or unreliable.

Whilst it’s true that police radios are all encrypted, and that for now the public is unable to decrypt these communications, they are still trackable.  They still send out radio waves on particular frequencies, and the relative signal strengths of individual communications can still give an idea as to location – more so if people put resources together to work in direction finding.  If it’s just necessary to know when a police radio is transmitting within a few metres of you (eg. the entrance to your street) then a Digi-Hunter would find it.

Police radios also have another (perhaps largely theoretical) weakness, they send out tones whilst nobody is transmitting but a connection is established.  These tones can often be heard for quite some distance if the radio is on loud enough, and so a microphone positioned in a suitable place could be linked to a device which detects the relevant ‘beep-boops’.

Another method which could be used unreliably is the method in which traffic lights detect oncoming emergency service vehicles and so change pre-emptively.  It’s unreliable because the technology used varies, and usually requires input from the driver (who obviously wouldn’t enable it to get past your sensor).  However, when placed beside existing traffic lights it could return interesting data regarding the coming and going of emergency vehicles over time.

And finally there’s the obvious, looking out the window for police cars, police in uniform (perhaps in undercover cars!), etc.  Facial recognition software used by government and corporate agencies are now quite highly developed, and so theoretically could be used to watch for police activity.  In practise, it would require the system to either watch for uniforms (which could be mistaken for other emergency services) or every single face of every single police officer.