CrossingGuard: exploring information content in navigation aids for visually impaired pedestrians

Visually impaired pedestrians experience unique challenges when navigating an urban environment because many cues about orientation and traffic patterns are difficult to ascertain without the use of vision. Technological aids such as customized GPS navigation tools offer the chance to augment visually impaired pedestrians' sensory information with a richer depiction of an environment, but care must be taken to balance the need for more information with other demands on the senses. In this paper, we focus on the information needs of visually impaired pedestrians at intersections, which present a specific cause of stress when navigating in unfamiliar locations. We present a navigation application prototype called CrossingGuard that provides rich information to a user such as details about intersection geometry that are not available to visually impaired pedestrians today. A user study comparing content-rich information to a baseline condition shows that content-rich information raises the level of comfort that visually impaired pedestrians feel at unfamiliar intersections. In addition, we discuss the categories of information that are most useful. Finally, we introduce a micro-task approach to gather intersection data via Street View annotations that achieves 85.5% accuracy over the 9 categories of information used by CrossingGuard.