People with visual disabilities have serious difficulties when mobilizing through the city on the public transportation system. We introduce AudioTransantiago, a handheld application that allows users to plan trips and provide contextual information during the journey through the use of synthesized voices. The usability and cognitive evaluation of AudioTransantiago was performed using a prototype evaluation in order to identify and solve usability issues, ending up with an intuitive and simple interface. Finally, a cognitive impact evaluation administered during bus trips taken with the assistance of AudioTransantiago demonstrated that the software provides more autonomy and effectiveness for users' trips, improving their orientation and mobility. © 2011 by Walter de Gruyter · Berlin · Boston.