Development of Mobile Accessible Pedestrian Signals (MAPS) for Blind Pedestrians at Signalized Intersections

Liao, Chen-Fu; Rakauskas, Michael E.; Rayankula, Avanish · 2011 · ROSA P / University of Minnesota. Intelligent Transportation Systems Institute

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Summary

This research addresses the significant safety and mobility challenges faced by blind and visually impaired pedestrians at signalized intersections. Blind individuals rely on auditory, olfactory, and tactile feedback for navigation, often struggling with locating crosswalks, determining safe crossing times, and maintaining alignment. Existing infrastructure-based Accessible Pedestrian Signals (APS) suffer from high costs, noise pollution, ambiguous directional cues, and difficult-to-locate pushbuttons. The study aims to develop a Mobile Accessible Pedestrian Signal (MAPS) system to provide decision support, potentially enhancing or replacing traditional APS by leveraging smartphone technology. The methodology involved a user needs analysis through interviews with ten blind and low-vision individuals to identify critical information requirements and technology preferences. Based on these findings, the researchers developed a MAPS prototype integrating smartphone sensors (GPS, digital compass, accelerometer) with wireless technologies (Wi-Fi and Bluetooth) to communicate with traffic signal controllers. The system provides Signal Phasing and Timing (SPaT) data and intersection geometry information. The user interface utilizes simple tactile inputs: a single-tap command retrieves intersection geometry (street name, direction, lane count), while a double-tap confirms the crossing direction and requests pedestrian phase timing. Feedback is delivered via Text-to-Speech (TTS) and tactile cues. Key findings from the user interviews yielded six design recommendations: auditory and tactile outputs must not interfere with cane use or traffic listening; tactile cues should warn of danger alongside auditory instructions; outputs should be short phrases; systems must allow warning repetition; additional intersection information is necessary; and the system should support automatic or user-activated signal requests. The prototype development demonstrated that smartphone sensors could capture heading and acceleration data, though GPS inaccuracy and sensor noise presented challenges. The MAPS system successfully integrated SPaT data to provide personalized signal timing and environmental context, addressing the ambiguity of traditional APS regarding which street has the walk signal. The significance of this work lies in the potential for MAPS to offer a more cost-effective, scalable, and user-centric alternative to infrastructure-based APS. By eliminating the need for physical pushbuttons and conduits, MAPS can be deployed more widely. The system also benefits users with low vision and distracted sighted pedestrians. The research concludes that while MAPS provides critical decision support, it complements rather than replaces learned wayfinding skills. Future work is required to evaluate usability, compare effectiveness against existing APS, and develop algorithms for veering alerts using pedestrian dead-reckoning and image processing.

Key finding

A smartphone-based prototype successfully integrated traffic signal controller data with mobile sensors to provide blind pedestrians with intersection geometry and signal timing information through simple touch commands.

Methodology

mixed_methods

Sample size: 10

Provenance

The full processing record for this entry. Every stage of this paper's journey through the pipeline is logged — what ran, with which tool and model, how many attempts it took, and when it last completed. Discovered via bulk_ingest_rosap on 2026-05-23 (6 acquisition events logged).

Summary generated by qwen3.6-27b-prismaquant on 2026-06-10; verification: verified.

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