StreetViewAI is the first accessible street view tool for people with visual impairments. Interactive streetscape mapping tools like Google Street View (GSV) and Meta Mapillary allow users to virtually explore and experience real-world environments through immersive 360-degree imagery, but they are fundamentally inaccessible to people with visual impairments. StreetViewAI solves this problem by combining context-aware multimodal AI, accessible navigation controls, and interactive voice. With StreetViewAI, people with visual impairments can virtually review destinations, explore the open world, and virtually travel across GSV's distributed collection of over 220 billion images and over 100 countries. Through an iterative design process with a mixed-vision team and evaluations with 11 visually impaired users, we demonstrated the value of accessible street view in supporting point-of-interest (POI) surveys and remote route planning. Finally, we list key guidelines for future research.