Browsing by Subject "Visually impaired persons"

Now showing 1 - 5 of 5
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    Deploy and Test a Smartphone-Based Accessible Traffic Information System for the Visually Impaired
    (Minnesota Department of Transportation, 2020-10) Liao, Chen-Fu; Davis, Brian
    An increasing number of Accessible Pedestrian Signals (APS) have been installed at new or upgraded intersections to assist people with vision impairment to navigate streets. For un-signalized intersections and intersections without APS, people with vision impairment have to rely on their own orientation and mobility skills to gather necessary information to navigate to their destinations. Previously, a smartphone-based accessible pedestrian system was developed to support wayfinding and navigation for people with vision impairment at both signalized and un-signalized intersections. A digital map was also created to support the wayfinding app. This system allows a visually impaired pedestrian to receive signal timing and intersection geometry information from a smartphone app for wayfinding assistance. A beacon using Bluetooth Low Energy (BLE) technology helps to identify a pedestrian's location when he or she travels in a GPS-unfriendly environment. A network of Bluetooth beacons ensures that correct traffic information is provided to the visually impaired at the right location. This project leverages the previous work by installing the system at a number of intersections in downtown Stillwater, Minnesota, where MnDOT operates the signalized intersections. In this study, researchers interface with the traffic controllers to broadcast traffic signal phasing and timing (SPaT) information through a secured and private wireless network for visually impaired users. The aim is to test the smartphone-based accessible system and evaluate the effectiveness and usefulness of the system in supporting wayfinding and navigation while the visually impaired travel through signalized and un-signalized intersections.
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    Development of a Navigation System Using Smartphone and Bluetooth Technologies to Help the Visually Impaired Navigate Work Zones Safely
    (Minnesota Department of Transportation, 2014-02) Liao, Chen-Fu
    According to statistics from the Federal Highway Administration (FHWA), each year approximately 17% of all work zone fatalities are pedestrians. People who are visually impaired often encounter physical and information barriers that limit their accessibility and mobility. A survey was conducted among 10 visually impaired participants as a starting point to understand their challenges and what types of information are helpful in providing bypass or routing instructions to them around work zones. The survey results were incorporated into development of guiding documents in determining information elements that are essential and useful for providing routing instructions to the visually impaired around work zones. Building on our previous efforts to provide geometry and signal timing to the visually impaired at signalized intersections, a smartphone-based navigation system was developed and integrated with navigational audible information to alert pedestrians at decision points prior to their arrival at a work zone. The recommended message elements from survey results were implemented in a smartphone app that uses GPS and Bluetooth technologies to determine a user’s location. When a work zone is detected, the smartphone will vibrate to alert users and the app will then announce a corresponding audible message to users. The visually impaired users can perform a single tap on the smartphone to repeat the messages, if needed. Functionality testing and system validation of the smartphone app were performed by attaching four Bluetooth beacons to light posts near a construction site in St. Paul, MN. Additional research is needed to conduct experiments with visually impaired users and evaluate system reliability and usefulness.
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    Development of Mobile Accessible Pedestrian Signals (MAPS) for Blind Pedestrians at Signalized Intersections
    (Center for Transportation Studies, 2011-06) Liao, Chen-fu; Rakauskas, Michael; Rayankula, Avanish
    People with vision impairment have different perception and spatial cognition as compared to the sighted people. Blind pedestrians primarily rely on auditory, olfactory, or tactile feedback to determine spatial location and find their way. They generally have difficulty crossing intersections due to lack of traffic information at intersections. Among the intersection crossing sub-tasks, locating crosswalk, determining when to cross and maintaining alignment to crosswalk while crossing are the most difficult tasks for the blind and visually impaired. To understand how the blind pedestrians make safe crossing decisions, ten blind and low-vision individuals were interviewed. The purpose of these interviews was to understand the types of information they use while making safe intersection crossings and identify new information types that could assist them. A Mobile Accessible Pedestrian Signals (MAPS) prototype was developed to support decision making at signalized intersections. The MAPS integrates sensors on a Smartphone, Wi-Fi, and Bluetooth technologies, and traffic signal controllers were developed to provide intersection geometry information and Signal Phasing and Timing (SPaT) to pedestrians who are blind at signalized intersections. A single-tap command on the Smartphone screen allows users to request for intersection geometry information, such as street name, direction and number of lanes at a corner of an intersection. A double-tap input while pointing toward desired direction of crossing will confirm the crossing direction, request for pedestrian phase, and the Smartphone application will then wirelessly request for signal timing and phasing information from traffic signal controller.
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    A Positioning and Mapping Methodology Using Bluetooth and Smartphone Technologies to Support Situation Awareness and Wayfinding for the Visually Impaired
    (Center for Transportation Studies, University of Minnesota, 2018-11) Liao, Chen-Fu
    People with vision impairment often face challenges while traveling in an unfamiliar environment largely due to uncertainty and insufficient accessible information. To improve mobility, accessibility, and the level of confidence the visually impaired experience in using the transportation system, it is important to remove information barriers that could potentially impede their mobility. A "condition aware" infrastructure using Bluetooth low-energy (BLE) technology was developed to provide up-to-date and correct audible information to users at the right location. A Multivariable Regression (MR) algorithm using the Singular Value Decomposition (SVD) technique was introduced to model the relationship between Bluetooth Received Signal Strength (RSS) and the actual ranging distance in an outdoor environment. This methodology reduced the environmental uncertainty and dynamic nature of RSS measurements in a Bluetooth network. The range output from the MR-SVD model was integrated with an extended Kalman filter to provide positioning and mapping solutions. Using 6 BLE beacons at an intersection in St. Paul, Minnesota, our approach achieved an average position accuracy of 2.5 m and 3.8 m in X and Y directions, respectively. A few statistical techniques were implemented and were able to successfully detect whether the location of one or multiple BLE beacons in a network changed based on Bluetooth RSS indications. With the self-monitoring network, information associated with each Bluetooth beacon can be provided to the visually impaired at the right location to support their wayfinding in a transportation network.
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    Using a Smartphone App to Assist the Visually Impaired at Signalized Intersections
    (Intelligent Transportation Systems Institute, Center for Transportation Studies, University of Minnesota, 2012-08) Liao, Chen-Fu
    The blind and Visually Impaired (VI) rely heavily on walking and public transit for their transportation needs. A major challenge for this population is safe crossing of intersections. As a result of the American with Disabilities Act (ADA), Accessible Pedestrian Signal (APS) systems at signalized intersections have improved significantly since 2000. However, these systems still have shortcomings for both users and municipalities, and new approaches are needed to adequately serve pedestrians with low vision. As part of our ongoing effort to develop a prototype Mobile Accessible Pedestrian Signal (MAPS) application for the blind and VI, we interviewed ten blind and lowvision people to better understand what types of information they use at intersection crossings and to identify information types that could assist them. With these survey results, a MAPS prototype was developed that provides signal and intersection geometry information to Smartphone users at signalized intersections. User interaction is via simple tactile input (single or double-tap) and Text-To-Speech (TTS) technology. A MAPS prototype was developed and tested to evaluate the functionalities of providing signal and orientation information to the visually impaired travelers at signalized intersections. This proposal will build upon the developed MAPS and investigate how blind and low-vision individuals gain their spatial knowledge surrounding an intersection and how the MAPS can be used to support their decision-making strategy at intersection crossings.