Accessible Pedestrian Signal Conflict Monitoring
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Solution Overview
Problem
Conventional malfunction management units in traffic light control systems are inadequate in recognizing and responding to conflicts or errors in non-visual pedestrian signal indications provided by accessible pedestrian signal (APS) systems, particularly for visually impaired pedestrians, as they are designed for basic visual traffic signal information and lack reliable control over multiple types of audible indications.
Innovation Solution
Integration of a conflict monitoring and error detection system within APS systems, including a primary conflict monitor and error detector that verifies actual signals against expected signals based on traffic states and user settings, and a secondary conflict monitoring subsystem that communicates via powerline communications to inhibit outputs in case of detected conflicts or errors, ensuring accurate and safe non-visual signal delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional malfunction management units are used in traffic light control systems, then the system structure remains simple and cost-effective, but the system cannot reliably recognize and respond to conflicts or errors in non-visual pedestrian signal indications
Solution Approach 1:
The patent applies universality by designing the malfunction management unit to handle both traditional visual traffic signal monitoring and the new APS non-visual signal monitoring functions. The MMU is enhanced to universally monitor multiple signal types (visual and non-visual) and respond to various failure modes, making it a multi-functional control unit that maintains system reliability without requiring completely separate monitoring systems.
Solution Approach 2:
The patent implements feedback mechanisms where the MMU continuously monitors the operational status of APS components (audible signals, vibrotactile outputs), compares actual performance against expected behavior, and automatically responds to detected conflicts or errors. This closed-loop feedback system enables reliable conflict detection and error response while maintaining manageable system complexity through automated monitoring and control.
2Adaptability or versatility
If APS systems provide multiple types of audible indications for different applications, then the system becomes more versatile and adaptable, but the complexity of monitoring and detecting conflicts increases
Solution Approach 1:
The patent applies local quality by implementing specific monitoring and detection logic tailored to each type of audible indication and signal application. Rather than using a single generic monitoring approach, the system employs specialized detection mechanisms for different signal types (e.g., walk indications, wait tones, pole locator tones), allowing complex conflict monitoring to be broken down into manageable, application-specific checks that maintain overall system versatility while controlling complexity.
Data Source
AI summary
Methods and systems are provided for conflict monitoring and error detection in accessible pedestrian signal systems. A primary conflict monitor and error detector is configured to control output of audible and vibrotactile pedestrian signal indications. The primary conflict monitor and error detector monitors the current traffic state, and verifies audio and vibrotactile control signals against the current traffic state and user settings to determine whether to enable output of audible and vibrotactile pedestrian signal indications. The primary conflict monitor and error detector may transmit information about the audio and vibrotactile control signals to a secondary conflict monitor and error detector, which verifies the information received against the current traffic state and user settings, and inhibits output of audible and vibrotactile pedestrian signal indications in the event of a detected conflict or error.