A location-aware navigation system has been developed and implemented for the visually disabled or visually impaired; the system is designed to improve individuals' independent mobility. This self-contained, portable system integrates several technologies, including mobile personal digital assistants, voice synthesis, a geographic information system (GIS), and a differential Global Positioning System (DGPS). The system is meant to augment the various sensory inputs available to the visually impaired user. It provides the user with navigation assistance, making use of voice cues iterating contextual building and feature information at regular intervals, through automatic GPS readings and a GIS database. To improve the efficiency of the retrieval of contextual information, an indexing method based on road segmentation was developed to replace the exhaustive search method. Experimental results show that the performance of the system on searching the buildings, landmarks, and other features around a road has been significantly improved by using this indexing method.