PREROLL applied to all speedometers in which the speed sensor is basically a Hall sensor with three pins. Change the phase that goes to the speedometer, and the tachograph, with the phase of the tachometer. For this method you need a working engine, and it's not very profitable. Very high risk of what will happen the failure of the device and even fire.
Get an electric a PREROLL, which is quiet and takes up little space. Such podmolik good speed regulation. Connect it to the diagnostic connector of the car. But remember that this method is applicable not on all cars.
The simplest electronic winding has three wires, which are mounted in the wiring. Disconnect the wire that goes with the standard speed sensor. Two wires connect to the power supply: the "plus" and "minus", and the third signal to the speedometer. Here the winding is temporary and removable, so the "box" in the wiring do better in an inconspicuous place.
For continuous use, connect the positive and negative leads of the winding in any convenient place in the car. The remaining two wires connect the break signal wire that connects the speedometer and transmission.
This way you will receive disconnect speed sensor when the PREROLL. Now you can fearlessly use your retrieve in all situations: in traffic, in the Parking lot. Conflicts system should not be.