Towns around my area regularly have radar operated "YOUR SPEED IS" mobile kiosks parked at major entrances to the town to slow people down. They have always matched the speed on my Zumo 550 exactly.
Here in Australia the mobile "kiosks" as you call them [ours are electronic LCD/LED sign units mounted on trailers, not sure what type of radar unit they use but they are often wrong- based on the consistency of several of my GPS units and compared to my speedo].
The important thing with comparing your GPS reading to your speedo reading is to make sure you are travelling at a consistent steady speed.
It takes 2-5 seconds for the signal between the GPS and the satellites to bounce back and be calculated and shown on the GPS screen.
I can make my GPS "lag behind" my speedo reading by up to 7kph under hard acceleration on my Wee-Strom.
When this happens the GPS starts to jump numbers on the reading as it tries to catch up to "real time" speeds- eg. with moderate acceleration it will start off 20,21,22,23, but if I gas it hard it then goes 20,27,35,40,43 etc. until my acceleration rate decreases and my speed becomes constant.
I have found by doing checks at different speeds while maintaining that speed steadily, the the speedo on my particular bike is off by near enough 10% throughout- GPS speed 80kph speedo reads 88kph, GPS 90 speedo 99, GPS 100 speedo 110, easy maths to maintain correct road speeds and when approaching a fixed or mobile speed camera I slow down and match the speedo to the posted limit which then actually ensures I'm under the limit.
It is also a fairly consistent known fact the the Strom speedo is, on average, actually off by 8% on the bulk of them.
For the record, I have 5 different GPS units- 2x Garmin, 2x TomTom, 1x Aldi GoCruise.
I have checked both my bikes plus my car using at least three different GPS units on/in the same bike/car, in each case the % variation between the speedo readings and the different GPS units remained consistent.
I'm happy my GPS units are accurate and I know in my head what the different speed reading variations are for each of my bikes and the car.
And if you are polite to a LEO when he stops you and you are only a bit over the speed limit and not endangering anyone, the odds are he will let you off with a warning.
Those :furious::furious: fixed and mobile cameras don't have the ability to assess the risk/danger factor for each infringement and are only there to fill the coffers of the government.
Here we have a tolerance of around 2kph-3kph from what we can gather [the powers that be in each State won't admit where they draw the line on being over].
The public uproar about the fact the cameras only raise revenue and don't actually reduce the road toll [statistics show they have in fact caused accident rates to rise at some camera sites because people "panic stop" to avoid a ticket thus actually causing multiple car rear enders- many of our cameras are combined red light/speed cameras at intersections] has caused at least one State government to start switching cameras off at some locations.