Yes, there are devices available on the civilian market that can display the speed of other vehicles on the road. These devices are commonly known as radar detectors or radar-based speed monitors. However, it's important to note that the legality of using radar detectors varies by country and even within different regions. Some countries or states may have specific regulations that restrict or prohibit the use of radar detectors. Therefore, it is essential to familiarize yourself with the laws and regulations in your specific jurisdiction before considering the use of such devices.
Radar detectors work by detecting the radar signals emitted by police speed enforcement devices, such as radar guns or lidar (light detection and ranging) guns. In addition to alerting drivers to the presence of speed enforcement devices, some advanced radar detectors can also display the speed of other vehicles nearby that are being targeted by these devices.
It's worth mentioning that relying solely on radar detectors to monitor the speed of other vehicles may not provide complete accuracy or reliability. Radar signals can be affected by various factors, including distance, weather conditions, and the type of radar technology used by law enforcement. Furthermore, radar detectors are not infallible and may not detect all speed enforcement devices in every situation.
It's always recommended to prioritize safe and responsible driving by adhering to speed limits and other traffic regulations. Radar detectors should be used in accordance with local laws and regulations, if permitted, and should not be seen as a means to encourage or engage in unsafe driving practices.