Establishing and Maintaining Direction for Street Crossing Using Nonvisual Cues
Billie Louise (Beezy) BentzenJanet M. Barlow
David A. GuthAlan C. Scott
Christopher M. Cunningham
TRANSED 2012 Delhi
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.
3
Need for alignment cues (before starting to cross the street)
Ramp slopes toward center of the intersection; pedestrian who is blind has to align on sloping surface, but counter to slope
Accessible Design for the Blind, 17/9/12, Slide
Accessible Design for the Blind, 17/9/12, Slide 4
Need for heading cues(while crossing the street)
Crosswalk is skewed. Thereis no trafficparallel to thecrosswalk.
Accessible Design for the Blind, 17/9/12, Slide 5
Research Goals
Determine surfaces or other cues that result in heading in the direction indicated by cue, despite slopeDetermine cues that result in maintaining directional heading across a wide street
Accessible Design for the Blind, 17/9/12, Slide 6
Three phases
“Lab” – testing variety of alignment cues on plywood ramps in parking lot
“Simulated crosswalks” – 24 m long, in large parking lot
On the street at actual intersections in three cities
Accessible Design for the Blind, 17/9/12, Slide 7
Cues tested on simulated curbramps1. Running Slope of ramp – no surface
installed on it—(approached from different angles)
2. Bar tile – perpendicular to direction of travel
3. Bar tile – parallel to direction of travel4. Truncated domes with bar perpendicular to
direction of travel5. Returned curb 6. Tactile arrow on pushbutton
Accessible Design for the Blind, 17/9/12, Slide 8
Detectable warning with bar
Accessible Design for the Blind, 17/9/12, Slide 9
Detectable warning with bar
Accessible Design for the Blind, 17/9/12, Slide 10
Slope only
Arrow
Returned curb
Bar tile-para
llel
Bar tile-perpendicu
lar
Detectable w
arning w
ith bar
0
2
4
6
8
10
1210.17 10.87
8.527.74
6.45 6.27
Average angular error in degrees
Accessible Design for the Blind, 17/9/12, Slide 11
Cues tested on simulated crosswalks—24m (6 lanes) long
Accessible Design for the Blind, 17/9/12, Slide 12
Bar tile - perpendicular
Accessible Design for the Blind, 17/9/12, Slide 13
Edgestrips
Accessible Design for the Blind, 17/9/12, Slide 14
Guidestrip
Accessible Design for the Blind, 17/9/12, Slide 15
RIAS (Talking Signs)
Accessible Design for the Blind, 17/9/12, Slide 16
Beaconing APS
Accessible Design for the Blind, 17/9/12, Slide 17
Users’ Experience – Beaconing Signal
1. 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 as far-side beacon from speaker at end of crosswalk
4. Users wait for walk signal5. Users hear walk signal from near-side pushbutton
only, and begin crossing6. 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 18
Results
At 4m all participants were within the crosswalk for all five conditions At 24m no participants were within the crosswalk for bar tile or RIAS At 24 m all participants were within the crosswalk for edgestrips, guidestrip and beaconing audible signal
Accessible Design for the Blind, 17/9/12, Slide 19
Intersection testing—Large, complex signalized intersections in
Alpharetta, GA, Towson, MD, and Austin, TX
Accessible Design for the Blind, 17/9/12, Slide
20
Standard audible and vibrotactile signal
Accessible Design for the Blind, 17/9/12, Slide 21
Beaconing audible and vibrotactile signal
Accessible Design for the Blind, 17/9/12, Slide 22
Tactile Guidestrip
Accessible Design for the Blind, 17/9/12, Slide 23
Results of intersection testing
Participants were more likely to stay within the crosswalk with either the guidestrip or beaconing than with standard audible signals.
Guidestrip Beaconing
Accessible Design for the Blind, 17/9/12, Slide 24
Results of intersection testingWhen participants veered outside the crosswalk in the standard audible signal condition, they seldom made a correction that brought them back into the crosswalk by the end of the crossing.
Accessible Design for the Blind, 17/9/12, Slide 25
Results of intersection testing
When participants veered outside the crosswalk in the beaconing signal condition, they often made a correction that brought them back into the crosswalk before the end of the crossing.
Accessible Design for the Blind, 17/9/12, Slide 26
Results of intersection testingWhen participants lost contact with the guidestrip, for instance when they had to go around a car that was across the crosswalk, they were sometimes unable to find the guidestrip again and veered far outside the crosswalk.
