Route Descriptions, Spatial Knowledge and Spatial Representations of Blind and Partially Sighted People: Improved Design of Electronic Travel Aids
Marion Hersh, Alasdair Ramirez Garcia · 2022 · ACM Transactions on Accessible Computing · doi:10.1145/3549077
Summary
This paper presents a qualitative study investigating how blind and partially sighted people acquire spatial knowledge, form mental maps, and describe routes—with the goal of informing better design of electronic travel aids (ETAs). The researchers worked with nine participants in Santa Catarina, Brazil, who walked two routes: an external urban route of approximately 900 meters involving traffic, pedestrians, and varied surfaces, and an internal route of about 300 meters within a foundation campus for people with visual impairments. The methodology combined think-aloud protocols during route walking, post-walk route descriptions, and semi-structured interviews. This rich qualitative approach captured not just what environmental features participants noticed, but how they processed and organized spatial information. The study is notable for being conducted in a real-world setting rather than a laboratory, and for its focus on understanding cognitive processes rather than measuring performance metrics. The analysis revealed that participants used complex multi-sensory strategies to identify objects and build mental representations. They combined tactile information (from white canes and feet), auditory cues (traffic sounds, echoes, voices), olfactory information (food vendors, vegetation), proprioceptive feedback (slopes, turns), and thermal sensations (sun, shade, air movement). Participants frequently made inferences beyond direct sensory input—hearing traffic and deducing a busy intersection, feeling a slope and concluding they were approaching a specific landmark. The paper emphasizes that blind travelers are active cognitive agents constructing sophisticated spatial models, not passive recipients of environmental information.
Key findings
Route descriptions were organized into four thematic categories: directions and actions (turn left, continue straight); warnings and alerts (traffic dangers, obstacles); surface and path features (slopes, textures, widths); and objects and locations (buildings, landmarks, open spaces). Participants differed in how much detail they included—some provided dense, feature-rich descriptions while others gave sparser directional guidance. Mental map formation relied heavily on landmark identification through multiple sensory channels. The external route generated more feature mentions (averaging 115 per participant) compared to the internal route (averaging 45), reflecting the greater complexity and variety of the urban environment. Tactile paving was the single most frequently mentioned feature on the external route, appearing 39 times in one participant's commentary. The study identified that current ETAs focus primarily on obstacle detection and fail to support the cognitive processes involved in mental map formation. Participants expressed desire for devices that could store and recall route information, provide landmark descriptions, and adapt to individual preferences and expertise levels. The authors propose that ETAs should incorporate memory functions, AI/ML personalization, spoken landmark provision, and interfaces for sharing route information with orientation and mobility instructors.
Relevance
This research is valuable for ETA developers and orientation and mobility professionals because it grounds design recommendations in detailed empirical observation of how blind travelers actually process spatial information. Rather than assuming what features matter, the study documents the rich multi-sensory strategies people employ. The findings challenge the obstacle-avoidance focus of most current ETAs. The paper argues convincingly that navigation involves much more than avoiding collisions—it requires building internal spatial models that support confident, independent travel. ETAs that only warn about obstacles miss the opportunity to support landmark learning, route memory, and spatial reasoning. For practitioners, the categorization of route description elements provides a useful framework for understanding what information matters to blind travelers. The emphasis on multi-sensory integration suggests that accessibility solutions should consider the full range of sensory channels, not just auditory output. The call for AI-enabled personalization reflects growing recognition that accessibility tools must adapt to individual users rather than assuming one-size-fits-all solutions.
Tags: electronic travel aids · blind navigation · mental maps · orientation and mobility · wayfinding · multi-sensory perception · route descriptions · spatial cognition