This paper introduces City Browser, a prototype multimodal, conversational, spoken language interface for automotive navigational aid and information access. A study designed to evaluate the impact of age and gender on device interaction errors, perceptions and experiences with the system along with physiological indices of workload is outlined. Preliminary results, plans for further analysis and a larger scale user evaluation are presented. Keywords Multimodal Interfaces, Speech I/O, User Interface Design, Usability Testing and Evaluation ACM Classification Keywords H5.2 Information Interfaces and Presentation (e.g. HCI): User Interfaces--graphical user interfaces, natural language, voice I/O; I2.7 Artificial Intelligence: Natural Language Processing--language parsing and understanding, speech recognition and synthesis; J4 Social and Behavioral Sciences: Psychology