In Car Speed Detection Devices

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There are many types of in-car speed detection systems in use by the UK Police Forces. This is just a short introduction to one or two.

VASCAR

Visual Average Speed Computer And Recorder. There are various other devices which are deigned and operated the same way, among them the Police Pilot. All these systems are highly accurate and have fail safe systems built in to ensure that all parts of the device are working correctly. If the system detects any errors, no matter how slight, the system aborts the speed check.

These devices are fitted into just about all traffic patrol cars across the country. The operators are very highly trained and the devices can work in a number of different ways which you may just find surprising!

Basically, what this device does is it measures the distance that a target vehicle travels and also the length of time that it takes. It then makes a very quick calculation and displays your average speed over that distance. The Police operator will activate the distance measuring device as your vehicle goes passed a fixed object at the road side, or the strange white dot's you sometimes see on the road surface. Ever wondered what they are? Well, traffic patrol officers refer to them as ‘vascar dots' because that's exactly what they are. The device then very accurately measures the distance travelled using readings from several sensors around the vehicle. Each one checks against the others and no errors at all are allowed. There are also two entirely separate and independent quartz clocks in the unit which measure the time taken to travel between two fixed points. Again, no errors are allowed by the system. If the clocks don't agree exactly the check is aborted.

Before using this device it must be calibrated. Even a minor change in tyre pressures can affect the accuracy of speed readings, so they must be re calibrated at least once a day. The operator does this by checking the unit against a fixed and highly accurate measured mile along the road. The unit is then re calibrated to show an accurate reading and is then ready for use.

The device can be used in many ways. It can be used whilst following a vehicle, it can be used to check a vehicle following the traffic car, it can have a pre set distance entered and be used whilst the patrol car is stationary or in a number of other ways.

The bottom line is that these devices are highly accurate and the operators are highly trained. Don't speed!

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