A road calibration system and a method for calibration of a road surveillance system are provided. The road surveillance system monitors a surveillance area of a road using vehicle surveillance devices. The vehicle surveillance devices measure a position of a vehicle passing the surveillance area and are synchronized with a global timing signal. In order to calibrate the vehicle surveillance devices such that a position determination of the vehicle surveillance devices is equal, a calibration vehicle with predefined calibration markers is passed through the surveillance area. During the passage each measurement device measures a position of an assigned calibration marker at a predetermined time and compares a measured distance between the positions of the calibration markers with a reference distance between the positions of the calibration markers.