re: driving offence - tradein The screen was inside the police...

re: driving offence - tradein The screen was inside the police car in the middle of the dashboard right?

So he was travelling the same direction as you but behind you. They are not supposed to trust the radar when other cars are nearby, especially when the other cars are travelling in the same direction. The reason is that the mobile radar has two speed sensors - one for the "closing speed" which is the speed difference between the two vehicles and the other is the "patrol speed" which is the speed of the police car. The mobile radar subtracts the patrol speed from the closing speed and therefore calculates the speed of the alleged speeder's car.

Shadow Effect
This relates to a problem with moving mode
radar, and is an issue of an incorrectly
displayed patrol car speed. The issue here is that
the police car is passing another vehicle
moving in the same direction. The radar in the
patrol car should be reading the ground speed,
but instead has lock-on to the other vehicle
travelling in the same direction, giving an
incorrect patrol speed.

For example, if the police car is actually doing
80 km/h, and the other vehicle is doing 40 km/h,
the patrol speed displayed would be 40 km/h.
The problem is, if the oncoming car is doing a
true 60 km/h, the closing doppler will still relate
to a closing speed of 140 km/h. The patrol speed
will be taken to be 40 km/h, so instead of a
displayed speed reading of 60 km/h, the actual
displayed speed will be 100 km/h.


Really, they shouldn't take a reading unless the police car and your car are separated from other cars. It actually says that in police instructions.


NSW highway patrol cars are now fitted with video cameras which have microphones. The officer will warn you that you are on camera when you are pulled up. The cameras cannot possibly hear what you say inside your car while driving along, but they can video your car during the alleged offence and when you are talking to the police officer, so if you throw a wobbly or offer to bribe the officer when you get booked there could be video evidence for a further charge.

It would be possibly a good move to request the video under freedom of info rules. The video might support your view of things, such as other cars in close proximity or some other thing.

The fine for under 15kph over the limit is $75. The fine for 15-30kph is $225. You lose three points now (since about 6 months ago) in both cases.