Abstract: A detector for identifying a road lane boundary using a digitalized optical image of the region in front of the vehicle. The detector includes a correlator configured to select the edges which are to be used for road lane estimation by searching for extreme values of convolution response, and to weight each convolution response by a weighting factor. A histogram analysis unit configured to group the extracted edges into pairs, and to determine a frequency distribution of the distances between two paired edges as a histogram, and to use said frequency distribution to determine the distances between two grouped edges forming a frequency peak or a frequency plateau in the histogram as nominal edge widths.