Radar speed sign

A speed indicator system (short GAA) is a technical device on the roadside, which serves the driver display its current speed. By a sensor, the vehicle speed is detected and displayed on a display. These systems are not used to traffic monitoring, as they have no camera and no license plate record, and they are also not to be confused with speed warning systems.


A radar beam at the frequency 24.125 GHz is sent to the approaching vehicles. From the radar reflectivity, the speed is determined and these are displayed on a large LED display with character height 307 mm and 180 ° viewing angle in real time. An integrated brightness meter the LED brightness is automatically adapted to the environment. It can reach speeds from 3 to 255 km / h processed at a measuring distance of up to about 80 meters (260 feet), the accuracy is given as ± 3%.

In a general internal memory data can be stored for statistical analysis, without that individual road users can be identified. The data memory can be read out via Bluetooth.


Speed ​​display systems are designed to make drivers aware of their possibly excessive speed through the large display of the measured velocity. Due to the very far recognizable indicator is to be effected according to the manufacturer a social component, since all the bystanders even at long range, can detect the speeding of Measured. Special design of the display system can with children artwork and text messages - such as " TOO FAST " or " THANK YOU " to be equipped. Depending on the model are also multi-colored number indicators (green for OK and red for too fast) possible.

The Insurers Accident Research ( UDV ) resulted in the published 2010 study "Evaluation of dynamic speed feedback" dynamic speed displays a comparison of these with the so-called dialogue display through. Although the dialog screen does not display the speed driven and praises only by the display of " thank you" and "Slow" and blames himself stronger and lasting declines in average speeds showed.