Accessible Pedestrian Signal (APS) Formerly Audible Pedestrian Signals.

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Transcript of Accessible Pedestrian Signal (APS) Formerly Audible Pedestrian Signals.

  • Slide 1
  • Slide 2
  • Accessible Pedestrian Signal (APS) Formerly Audible Pedestrian Signals
  • Slide 3
  • What is an APS? Accessible Pedestrian Signal - a device that communicates information about pedestrian timing in nonvisual format such as audible tones, verbal messages, and/or vibrating surfaces. (US-MUTCD 2000, Section 4A.01) [I acknowledge for some data provided: for new sounds ]
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  • Other terms APS are known by different names in different countries: Acoustic signals Audio-tactile signals Audible pedestrian signals Audible pedestrian traffic signals Audible traffic signals Audible crossing indicators
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  • Major functions of APS APS can provide information to pedestrians about: Existence of and location of the pushbutton Existence of the Walk [and DW] intervals Direction of the crosswalk and location of the destination curb Intersection geometry through maps, diagrams, or speech Intersection street names in Braille, raised print, or speech Intersection signalization
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  • Visual impairment Normal Vision - Vision correctable to 20/20 with at least 180-degree field is considered 'normal vision
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  • Visual impairment A functional limitation in seeing, including those with: "non-severe limitation" ("difficulty seeing words and letters") and those with "severe limitation" ("unable to see words and letters") Legal blindness: a level of visual impairment that has been defined by law to determine eligibility for benefits
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  • Visual impairment A person who is legally blind sees at approximately 20 feet what a person with 20/20 vision sees at 200 feet Or is able to see no more than a 20-degree field without scanning
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  • Reduced acuity
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  • Central field loss
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  • Peripheral field loss
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  • Decrease in attentional field Research by Brabyn, Haegerstr m-Portnoy, Schneck, and Lott (2000) demonstrated that over age 60-65 the prevalence of problems detecting objects in the peripheral visual field increases dramatically. This is known as a decrease in attentional field, and it may be present with or without other types of visual impairment
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  • Decrease in attentional field By age 90, 40% of people have an attentional field of less than 10 degrees left and right. Thus, if they are looking at a ped head, they are unlikely to be visually aware of vehicles that may be disobeying the signal, or turning across their path of travel, until it is too late to take appropriate action
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  • Total blindness or light perception Individuals who are considered totally blind usually cannot see any difference in light and dark Individuals who have light perception may be able to tell if it is dark or light and the direction of a bright light source, but do not have vision that is useable for discerning objects or the travel path
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  • Prevalence of blindness Some degree of vision impairment affects 8.3 million (3.1%) Americans of all ages (Adams, Hendershot, & Marano, 1999) Approximately 3% of individuals age 6 and older, representing 7.9 million people, have difficulty seeing words and letters in ordinary newspaper print even when wearing glasses or contact lenses. This number increases to 12% among persons age 65 and older (3.9 million) (McNeil, 2001). Approximately 1.3 million Americans are legally blind
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  • Prevalence of blindness By 2010, projections are that there will be 20 million visually impaired persons over 45
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  • Area of residence Most persons who have a vision impairment live in metropolitan areas (70%) 33% live in cities, 37% live in suburbs, 28% live in non- metropolitan areas (e.g., small towns) and 1% live in farm areas (Schmeidler & Halfmann, 1998b) In comparison to the general population, persons who are visually impaired are over-represented in cities and non- metropolitan areas and somewhat under-represented in the suburbs (i.e., 48% of general population live in suburbs) (Schmeidler & Halfmann, 1998b)
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  • What can be done? ?
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  • Intersection design Wider streets require more precise alignment Wide radius turns make alignment more difficult and increase crosswalk length Curb ramps and depressed corners make street detection and alignment difficult Medians and islands complicate wayfinding and alignment
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  • Intersection design Slip lanes and splitter islands require crossing in gaps in traffic even at signalized intersections Crosswalk alignment is not consistent Curb extensions, also called bulb-outs or intersection chokers, sometimes complicate wayfinding
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  • Intersection design Raised crosswalks may obliterate the sidewalk/street boundary Tabled intersections may also obliterate the sidewalk/street boundary Intersection signalization has become more complex
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  • Driver behavior& auto technology Aggressive drivers are moving faster and less likely to stop for pedestrians The technology of cars, including electric cars, has become quieter, making them harder for pedestrians who are visually impaired to hear In many areas there is less pedestrian traffic and less awareness of pedestrians by drivers
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  • Control Issues The techniques which worked at pretimed lights controlled by mechanical controllers are not adequate for intersections which change minute by minute in response to vehicular and pedestrian actuation. These changes affect the ability of pedestrians who are blind or visually impaired to recognize the pedestrian phase
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  • Proposed CNIB Standard Draft Accessible Pedestrian Signal recommendations {to TAC last fall} reflect the latest research and technology and the expertise of the members of a national Committee, which was formed by the Canadian National Institute for the Blind to advise on this matter The Committee has representatives from across Canada and includes people who are blind, visually impaired and deafblind, orientation and mobility specialists, traffic engineers and consumer advocates
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  • Proposed CNIB Standard The proposed standard has two levels of operation. Level 1 is a low-level tone for location, audible within 3m. Generally meant for fixed time operation - no ped calls. Level 2, if you hold the ped button in for 3 or more seconds, you will get the high level tones for Walk and Ped Clearance.
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  • Report Contents Introduction 1. Framework - The creation of the Committee - Principles - Mandate - Approach to the task 2. Navigating intersections: the skills used by pedestrians who are blind, visually impaired or deafblind 3. An implementation strategy 1. Framework 2. Navigating intersections: the skills used by pedestrians who are blind, visually impaired or deafblind 3. An implementation strategy II Definitions of Words and Terms III -- Features of an Accessible Pedestrian SignalII Definitions of Words and Terms III -- Features of an Accessible Pedestrian Signal 1. Required features of an APS 1.1 Operating period 1.2 Locator tones 1.3 WALK indication 1.4 Clearance indication tone 1.5 Activation 1.6 Volume1. Required features of an APS 2. Pushbutton 2.1 Size 2.2 Surface 2.3 Operating force 2.4 Visual contrast 2.5 Location 2.6 Locator tone 2.7 Activation indicator 2.8 Voltage 2. Pushbutton 3. Pushbutton Pole location 3.1 Visual contrast 3.2 Mounting height 3.3 Location - Adjacent to landing - Proximity to approach - Close to sidewalk - Proximity to curb or transition ramp - Separation 3.4 Location exception 3.5 Maximum distance 3.6 Crossing time 3. Pushbutton Pole location
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  • Report Contents 4. Pushbutton signage 4.1 Signage location 4.2 Tactile arrow 4.3 Universal symbol 4.4 Street name 4.5 Characters - Braille - Tactile characters - Stroke thickness and cross-section - Lettering 4.6 Indication of number of lanes4. Pushbutton signage 5. Locator tone 5.1 Volume 5.2 Repetition rate 5.3 Vibrotactile element 5.4 Availability 5.5 Single pole exception 5.6 Frequency range of pole locator tone 5.7 Location of locator tone speaker5. Locator tone 6. Operational modes 6.1 Two-phase operation without pushbutton 6.2 Two-phase operation with pushbutton 6.3 Multi-phase operation 6.4 Rest in Walk operation 6. Operational modes 7. APS deactivation 7.1 Operation period 7.2 Suspended operations 7. APS deactivation 8. Audible walk and clearance sounds 8.1 Tones 8.2 Recommended tones 8. Audible walk and clearance sounds 9. Augmented features 9.1 Activation 9.2 Augmented features 9.3 Augmented optional features 9. Augmented features 10. Other requirements 10.1 APS support elements 10. Other requirements
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  • Proposed Features 1.1 Operating period An APS must be operational at all times and not limited in operation by time of day or day of week 1.2 Locator tones Where an APS is controlled by a pushbutton, a locator tone must be used. 1.3 WALK indication When indicating the WALK interval, the APS must deliver the indication in audible and vibrotactile format. It is not sufficient for signals to provide accessible information only in vibrotactile format. 1.4 Clearance indication tone The APS must h