audible beaconing to help pedestrians who are blind cross streets billie louise (beezy) bentzen...
TRANSCRIPT
Audible Beaconing to Help Pedestrians Who are Blind
Cross Streets
Billie Louise (Beezy) BentzenJanet M. Barlow
David GuthAlan C. Scott
TRANSED 2012
Accessible Design for the Blind, 17/9/12, Slide 2
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 3
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 lotAccuracy of crossing significantly better with far-side signal
Accessible Design for the Blind, 17/9/12, Slide 4
Problems with Far-side Walk Signal Beacons
Too noisy to be tolerated in a neighborhoodThe far-side walk signal for one crosswalk might be mistaken for the signal for another crosswalkThe 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 5
A Prototype Developed to Avoid the Problems
Comes on only in response to a button-press of 1 sec or longer—seldom heardComes on only for the crosswalk where the button is pushedUnlikely 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 6
Components of APS with Far-side Beacon
Accessible Design for the Blind, 17/9/12, Slide 7
Users’ Experience1. Users hear locator tone from pushbutton2. Users push and hold button for at least 1 sec3. Users hear alignment tone--7 repetitions of
locator tone audible from far-side speaker4. Users wait for walk signal—quiet locator tone
continues5. Users hear walk signal from near-side APS only,
and begin crossing6. When walk signal ends, users hear far-side
beacon (loud locator tone) during pedestrian clearance interval, while crossing is completed
Tested in Charlotte, North Carolina16 participants made total of 48 crossings with and without far-side beaconingBeaconing resulted in improvement in crossing within the crosswalk
Accessible Design for the Blind, 17/9/12, Slide 9
More Intersection Testing—Alpharetta, GA, Towson, MD, Austin, TX
Compared crossings using far-side beacon APS, standard APS, and tactile guidestripFar-side beacon and tactile guidestrip resulted in good accuracyParticipants enthusiastic
about far-side beacon
Accessible Design for the Blind, 1/10/2010, Slide 10
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, 17/9/12, Slide 11
Trying to Cause Trouble in Portland, OR
Characteristics of the intersectionCrossings were 2-5 lanes wide Buildings on all corners3 crossings without good parallel traffic cues3 crossings not well aligned with direction of approach5 crossings
Accessible Design for the Blind, 17/9/12, Slide 12
43rdAve & Sandy Blvd
Hancock Street
Sandy Blvd
43 Ave
Accessible Design for the Blind, 17/9/12, Slide 13
4 Crosswalks Used for Experiment
Hancock Street
Sandy Blvd
43 Ave
Accessible Design for the Blind, 17/9/12, Slide 14
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 beaconingAPS with far-side beaconingAPS with far-side beaconing, with experimenter calling walk signal for another crosswalk— “confusion trials”
Accessible Design for the Blind, 17/9/12, Slide 15
Results for Portland Experiment
Accessible Design for the Blind, 1/10/2010, Slide 16
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, 17/9/12, Slide 17
APS with far-side beaconing—participants often observed to correct their heading;
no diagonal crossings
Accessible Design for the Blind, 17/9/12, Slide 18
APS with far-side beaconing and “confusion”
No confusion noted
Accessible Design for the Blind, 17/9/12, Slide 19
Conclusions
APS with far-side beaconingEnable blind pedestrians to maintaining or correct their heading so they usually cross within the crosswalk
Accessible Design for the Blind, 17/9/12, Slide 20
Conclusions
APS with far-side beaconingEnable blind pedestrians to maintaining or correct their heading so they usually cross within the crosswalkDo 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 21
Conclusions
APS with far-side beaconingEnable blind pedestrians to maintaining or correct their heading so they usually cross within the crosswalkDo not result in confusion about which crosswalk has the walk signal even when another person actuates beaconing for another crosswalkCan 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 22
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 crossingsAt intersections where there are reflective buildings near the corners
Accessible Design for the Blind, 17/9/12, Slide 23
Cautions
APS with far-side beaconing Should be actuated by an extended button-press
Accessible Design for the Blind, 17/9/12, Slide 24
Cautions
APS with far-side beaconing Should be actuated by an extended button-pressDo 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 25
Cautions
APS with far-side beaconing Should be actuated by an extended button-pressDo not need to be programmed for all crossings at an intersection; e.g. short crossings or crossings with reliable parallel trafficShould have especially careful attention to sound-level adjustment—no louder than necessary
Accessible Design for the Blind, 17/9/12, Slide 26
For additional information:
Contact Beezy Bentzen