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Audible Beaconing to Help Pedestrians Who are Blind Cross Streets. Billie Louise (Beezy) Bentzen Janet M. Barlow David Guth Alan C. Scott TRANSED 2012.
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Audible Beaconing to Help Pedestrians Who are Blind Cross Streets Billie Louise (Beezy) Bentzen Janet M. Barlow David Guth Alan C. Scott TRANSED 2012
This project was supported by Grant #5 R01 EY12894-07 from the National Eye Institute, National Institutes of Health. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the National Eye Institute. Accessible Design for the Blind, 17/9/12, Slide
A Far-side Walk Signal Gives Good Results at a Simulated Crosswalk • Compared simultaneous signals from both ends of crosswalk, signals alternating from one and to the other, and far-side signal, • 16 m long (4-lane) crosswalk simulated in a parking lot • Accuracy of crossing significantly better with far-side signal Accessible Design for the Blind, 17/9/12, Slide
Problems with Far-side Walk Signal Beacons • Too noisy to be tolerated in a neighborhood • The far-side walk signal for one crosswalk might be mistaken for the signal for another crosswalk • The far-side signal wouldn’t work if people on both ends of a crosswalk pushed the button to cross during the same cycle Accessible Design for the Blind, 17/9/12, Slide
A Prototype Developed to Avoid the Problems • Comes on only in response to a button-press of 1 sec or longer—seldom heard • Comes on only for the crosswalk where the button is pushed • Unlikely to have 2 pedestrians holding the button down for the same crosswalk during the same cycle Accessible Design for the Blind, 17/9/12, Slide
Components of APS with Far-side Beacon Accessible Design for the Blind, 17/9/12, Slide
Users’ Experience • Users hear locator tone from pushbutton • Users push and hold button for at least 1 sec • Users hear alignment tone--7 repetitions of locator tone audible from far-side speaker • Users wait for walk signal—quiet locator tone continues • Users hear walk signal from near-side APS only, and begin crossing • When walk signal ends, users hear far-side beacon (loud locator tone) during pedestrian clearance interval, while crossing is completed Accessible Design for the Blind, 17/9/12, Slide
Tested in Charlotte, North Carolina • 16 participants made total of 48 crossings with and without far-side beaconing • Beaconing resulted in improvement in crossing within the crosswalk
More Intersection Testing—Alpharetta, GA, Towson, MD, Austin, TX • Compared crossings using far-side beacon APS, standard APS, and tactile guidestrip • Far-side beacon and tactile guidestrip resulted in good accuracy • Participants enthusiastic about far-side beacon Accessible Design for the Blind, 17/9/12, Slide
But is Far-side Beaconing Safe? • What if the intersection is not very wide? • What if there are reflective buildings on the corners? • What if two people at the intersection request a far-side beacon during the same cycle? Accessible Design for the Blind, 1/10/2010, Slide
Trying to Cause Trouble in Portland, OR Characteristics of the intersection • Crossings were 2-5 lanes wide • Buildings on all corners • 3 crossings without good parallel traffic cues • 3 crossings not well aligned with direction of approach • 5 crossings Accessible Design for the Blind, 17/9/12, Slide
43rdAve & Sandy Blvd Hancock Street Sandy Blvd 43 Ave Accessible Design for the Blind, 17/9/12, Slide
4 Crosswalks Used for Experiment Hancock Street Sandy Blvd 43 Ave Accessible Design for the Blind, 17/9/12, Slide
Method • 22 participants who had little or no vision made 2 round-trip crossings of each experimental crossing • Each crossing had one of 3 beaconing conditions • Standard APS—no beaconing • APS with far-side beaconing • APS with far-side beaconing, with experimenter calling walk signal for another crosswalk— “confusion trials” Accessible Design for the Blind, 17/9/12, Slide
Results for Portland Experiment Accessible Design for the Blind, 17/9/12, Slide
Standard APS--participants tended to veer out of the crosswalk, and did not successfully correct their heading; some diagonal crossings Accessible Design for the Blind, 1/10/2010, Slide
APS with far-side beaconing— participants often observed to correct their heading; no diagonal crossings Accessible Design for the Blind, 17/9/12, Slide
APS with far-side beaconing and “confusion” No confusion noted Accessible Design for the Blind, 17/9/12, Slide
Conclusions APS with far-side beaconing • Enable blind pedestrians to maintaining or correct their heading so they usually cross within the crosswalk Accessible Design for the Blind, 17/9/12, Slide
Conclusions APS with far-side beaconing • Enable blind pedestrians to maintaining or correct their heading so they usually cross within the crosswalk • Do not result in confusion about which crosswalk has the walk signal even when another person actuates beaconing for another crosswalk Accessible Design for the Blind, 17/9/12, Slide
Conclusions APS with far-side beaconing • Enable blind pedestrians to maintaining or correct their heading so they usually cross within the crosswalk • Do not result in confusion about which crosswalk has the walk signal even when another person actuates beaconing for another crosswalk • Can safely be used at medium-sized intersections even where there are reflective buildings on the corners Accessible Design for the Blind, 17/9/12, Slide
Recommendations APS with far-side beaconing may be used to provide wayfinding information • At crossings where there is insufficient or inconsistent directional information from traffic, or very wide crossings • At intersections where there are reflective buildings near the corners Accessible Design for the Blind, 17/9/12, Slide
Cautions APS with far-side beaconing • Should be actuated by an extended button-press Accessible Design for the Blind, 17/9/12, Slide
Cautions APS with far-side beaconing • Should be actuated by an extended button-press • Do not need to be programmed for all crossings at an intersection; e.g. short crossings or crossings with reliable parallel traffic Accessible Design for the Blind, 17/9/12, Slide
Cautions APS with far-side beaconing • Should be actuated by an extended button-press • Do not need to be programmed for all crossings at an intersection; e.g. short crossings or crossings with reliable parallel traffic • Should have especially careful attention to sound-level adjustment—no louder than necessary Accessible Design for the Blind, 17/9/12, Slide
For additional information:Contact Beezy Bentzenbbentzen@accessforblind.org Accessible Design for the Blind, 17/9/12, Slide