Wrong honey.
Current Police radar techology is Ka Band DSP run technology. Using good old fashioned doppler calculations. Same as Lidar (Laser), it uses doppler calculations to work out your speed, of course the problem with Lidar is it can only track on 'object', ie not the ground (or background), so Lidar has to be used stationary.
Most older radar detectors have problems detecting Ka band. The new ones pick it up easily. However new Ka Instand on radar is virtually undetectable in standby mode, the only thing that gives it away is when they 'fire' instant on the signal is much stronger than usual and can be picked up around 10km away. So on the open road you get fairly good warning as long as theres other traffic around.
Because Lidar and Ka band use doppler calculations they also give a lower speed reading as the angle of deflection reading the speed increases. IE, at 0 degrees offset (12 o'clock) the reading is perfect, at 90 degrees the reading is 0 (zero), at 180 degrees (6 o'clock) the reading is perfect.
In NZ our Police are equiped wayyyyyy ahead of the US cops in terms of speed detection. All highway patrol type vehicles have Ka band (digital) as well as Lidar (Laser), stand patrol vehicles have K band (analog). We also have Ka band Speed Photo Radar in mobile vehicles, and pressure trigger mounted speed photo camera's in permanant mountings.
Currently in NZ if you exceed the speed limit by 10km/h you HAVE to be booked. They are trying to lower it to 5km/h. IE, do 105km/h in a 100km/h zone you get booked. Plus we have demerit points, too many points (about 4 speeding tickets) and you lose your license for up to 2 years.
As funked said, for the most part its nothing more than revenue collection. As an example, near where I live there is a stretch of highway which is a real killer. We used to live on a the main road leading up to it. Every weekend we would hear the ambulances (and before the soap box bunch talker about ambulances responding to speeders like me, more than often it was an old fart losing control and crossing into the oncoming traffic). Anyway, Govt refuses to build an alternative route recommended by a roading study. No, they're keen on getting more cameras out there.
I do a fair bit of travelling, hence the 'countermeasures' collection
Originally posted by funkedup
Yep the system they have figures in the speed of their car. They get a relative speed from the gun then subtract out their speed. The answer (assuming the gun is working right) is actually conservative, because I don't believe they factor in the lateral offset between the lanes.
Speed laws are basically a road usage tax. If you want to use the roads as God and Henry Ford intended them to be used, you have to pay a little extra.
