  Blind and low-vision (BLV) people rely on GPS-based systems for outdoor
navigation. GPS's inaccuracy, however, causes them to veer off track, run into
obstacles, and struggle to reach precise destinations. While prior work has
made precise navigation possible indoors via hardware installations, enabling
this outdoors remains a challenge. Interestingly, many outdoor environments are
already instrumented with hardware such as street cameras. In this work, we
explore the idea of repurposing existing street cameras for outdoor navigation.
Our community-driven approach considers both technical and sociotechnical
concerns through engagements with various stakeholders: BLV users, residents,
business owners, and Community Board leadership. The resulting system,
StreetNav, processes a camera's video feed using computer vision and gives BLV
pedestrians real-time navigation assistance. Our evaluations show that
StreetNav guides users more precisely than GPS, but its technical performance
is sensitive to environmental occlusions and distance from the camera. We
discuss future implications for deploying such systems at scale.
