Traffic signs with built-in Doppler radar measure and show vehicle speed with 2 (0-99 km/h) or 2+1/2 LED digits (0-199 km/h). Signs are in compliance with European standard EN12966. For use on city streets, regional roads and highways, in three sizes. Modular design ensures simple maintenance by simple replacements of the parts. LEDs with high luminous intensity and long life time. Special system to protect LEDs from temperature peeks that might happen during device operation. Possible brightness control: manual brightness control, brightness control according to actual day time using precise algorithm, brightness control according to external illumination measured by 1 or 2 light sensors and external brightness control. Communication interfaces: RS232, RS485, Ethernet, Wi-Fi, GSM/GPRS. Besides showing actual vehicle speed, the sign can also show some additional information like text information (SLOW DN, SLOW DOWN,…) or activate two or four flashers if speed is higher than allowed.