The first step in all previous works is image segmentation process. It aims at locating the regions of interest and features of road signs and determining the type of a detected sign (de la Escalera et al., 1997; Paclík et al., 2000; Piccioli et al., 1996, Gao et al., 2006). In segmentation and detection, traditionally color information was primarily used (de la Escalera et al., 2003; de la Escalera et al., 1997; Gao et al., 2006; Janssen et al., 1993; Piccioli et al., 1996). Other approaches use shape based detection with the geometrical edge analysis (Gao et al., 2006; Garcia-Garrido et al., 2006; Piccioli et al., 1996) or corner analysis (de la Escalera et al., 1997).