Signalized Intersection Crossing for the Visually Impaired

Transcription

1 Signalized Intersection Crossing for the Visually Impaired Chen-Fu Liao Minnesota Traffic Observatory Department of Civil Engineering University of Minnesota 23rd Annual CTS Research Conference May 23-24, St. Paul River Centre

2 Acknowledgements RITA, USDOT and UMN ITS Institute Vision Loss Resources (VLR) MnDOT Steve Misgen & Tim Bangsund Linda Spaulding Certified O&M Specialist Avanish Rayankula, Sowmya Ramesh Graduate Research Students Kale Fischer, Jean Mullins CTS Student Helpers Gordon Legge Department of Psychology Michael Manser HumanFIRST Program Herbert Pick Institute of Child Development Henry Liu Department of Civil Engineering

3 Outline Background Motivation and Our Approach Results from UI Survey Prototype & Demo Field Experiment Experiment Results Concluding Remarks

4 Low Vision Statistics Every 7 minutes someone in U.S. becomes blind or visually impaired More than 3.4 million (3%) Americans 40 years and older are legally blind or visually impaired By 2030, the number of blind and visually impaired people is predicted to double Alliance for Aging Research. (2010). The Silver Book: Vision Loss. Improving the Nation s Vision Health.

5 Potential Challenges at Crossings No intersection geometry information Locate the edge of street Locate crosswalk Interpret signal & traffic patterns Align toward crosswalk Locate pushbutton, if exists Determine when to cross Maintain alignment while crossing

6 Intersection Crossing 48.6% of crossings started during walk interval and 26.9% of all crossings (w/o assistance) ended after the onset of the perpendicular traffic Barlow et al. (2005) 72% started with appropriate alignment, 42% ended outside the crosswalk Barlow et al. (2005) Train pedestrians to use new cues or enhance their judgments with technology may be a more effective method of reducing crash events Guth et al. (2005)

7 Latest Generation of APS Audible and/or vibrotactile WALK signal indications Pushbutton locator tone - repeats constantly at 1Hz to provide information about the presence and location of a pushbutton Tactile arrow that points in the direction of travel on the crosswalk Automatic volume adjustment

8 Concerns about APS Costs - $6,000 per intersection plus labor Noisy. Add 5 decibels of noise within 6 to 12 feet of pushbutton Require additional stub, pushbutton station poles Pushbutton location Braille verification

9 APS at SE University & Berry St. LRT Westgate Station

10 Motivation Controversy in blind communities Provide personal pedestrian signal information with properly design user interface Intersection geometry information Blind pedestrian needs to locate and push the walk button by listening to separate audible cue Audible messages are often confused with noises in the vicinity and heavy rush hour traffic

11 Recommendations from the VI Summary of survey results Present additional information about the intersection Use short auditory phrases Auditory and tactile information should not interfere with the pedestrian s ability to use their cane or listen to traffic cues Use tactile cues for dangerous warnings A method to repeat warnings / output is necessary Allow for automatic activation of walk signal request at an intersection; or Allow the user to activate the signal though the mobile APS device

12 Mobile APS User Interface Geometry Information Single tap for orientation and geometry information Text-to-Speech message Heading North to Washington Ave 4-Lane Heading West to Oak Street 4- Lane

13 Mobile APS User Interface Signal Information Double tap to confirm crossing Send walk phase request to traffic signal controller Obtain signal timing information Walk, 20 sec to cross Wait for walk signal

14 System Diagram of MAPS Data Communications TS2 Traffic Signal Controller Cabinet USB I/O Wires to Pushbutton UMN VPN 3G or Wi-Fi SPaT Data Acquisition Synchronous Data Link Control (SDLC) Firewall MAPS DB Server 3G or Wi-Fi Smartphon e MnDOT Network

15 Field Experiment Sites Golden Valley, MN Winnetka Ave and Golden Valley Rd, Crossing Winnetka 5 lanes Cross from NW corner to NE corner Crossing time Approx 22 seconds APS equipped Minnesota Highway 55 & Rhode Island Ave N, Crossing Rhode Island Ave. 5 lanes, 111 ft Crossing from NE corner to NW corner Crossing time 23 sec. ü Walk 7 sec ü Don t Walk 16 sec No APS installed

16 Experiment Tasks Origin Walk 100~200 ft toward intersection Destination Crossing

17 System Evaluations Subjective Measures Sufficient info needed to cross intersection Sufficient time to cross Feel safe during crossing Usefulness & satisfaction (Van der Laan et al, 1997) Trust (Lee & Moray, 1992) Objective Measures Walk speed at sidewalk Walk speed at crosswalk Initial alignment Time to step into crosswalk Veering and # of veering # of assistance needed from O&M specialist

18 Visually Impaired Participants 11 Male, 7 Female Age average 44.2 years (SD 15.2 years) 12 cane users, 5 guide dog users, 1 use both 6 totally blind, 12 legally blind Cane users average 14.2 years (SD 14.1, Max 49) Guide dog users average 7.1 years (SD 5.7, Max 15)

19 Crossing Freq. & Phone Ownership More than 4 intersections a day Intersection Crossing Frequency 5 1 to 2 intersections a day to 4 intersections a week Mobile Phone Ownership Less than 1 intersection a week No phone Smartphone Non-smartphone

20 Self-Assessment Navigation & Wayfinding Preferred Method of Navigation Assistance Cane Guide dog Asking others No outside asstance Other Travel Skills - General Sense of Direction Well below Below Average Above Well above Travel Skills - Independent Travel Travel Skills - Signalized Street Crossing Well below Below Average Above Well above 0 Well below Below Average Above Well above

21 Intersection #1 (APS) Intersection #1 Responses No Yes Don't Know Use GPS Navigation Previously Have Prior APS Experience Prefer Pushbutton (PB) over No PB Have Difficulty in Locating PB APS Provides Sufficient Info Have Sufficient Time to Cross Feel Aligned to Crosswalk

22 Intersection #2 (Non-APS) Intersection #2 Responses No Yes Note Prefer Pushbutton (PB) over MAPS Both 1 - Neither Have Difficulty in Locating PB* Have Sufficient Time to Cross Feel Aligned to Crosswalk MAPS Provides Sufficient Info MAPS Provides Helpful Geometry Info MAPS Provides Helpful Signal Timing Info Unknown

23 Objective Measures Intersection ID 1 2 Intersection Type APS Non APS Crosswalk Length, meter (ft) 28.7 (94) 33.8 (111) Crossing Task # Sample Size (N) Ped Call APS PB Regular PB MAPS Crosswalk Speed, Average (mph) Crosswalk Speed, SD (mph) Sidewalk Speed, Average (mph) Sidewalk Speed, SD (mph) Sidewalk vs. Crosswalk Speed (p-value) Pushbutton Search Time, Average (sec) NA Pushbutton Search Time, SD (sec) NA In-Position Time, Average (sec) In-Position Time, SD (sec) Time to Step Into Crosswalk, Average (sec) Time to Step Into Crosswalk, SD (sec) Number of Veers Outside Crosswalk 4 2 4

24 Usefulness & Satisfying Useless Unpleasant Bad Annoying Superfluous Irritating Worthless Undesirable Sleep-inducing Satisfying Usefullness & Satisfying 17 Participants Mean Cronbach's α = 0.96 Useful Pleasant Good Nice Effective Likeable Assisting Desirable Raising Alertness Van der Laan et al. (1997) Usefullness

25 System Trust and Confidence Confidence (6) 65% Overall (3,9) 57% Purpose (7,8) 79% Process (2,5) 71% Performance (1,4) 65% 0% 25% 50% 75% 100% Lee and Moray (1992)

26 Decision Support System Our goal is to provide decision support for the visually impaired, elderly, or disabled at signalized intersections Not to replace the orientation and mobility skills they already learned Complement existing APS system Provide an integrated solution for navigation, wayfinding and guidance

27 Future Directions & Opportunities Application for elderly or disabled Work zone bypass and routing Orientation and direction support at bus stops (transfers, route # and arrival time) Veering warning Wayfinding and navigation ü Indoor (e.g. Minneapolis skyway) ü Outdoor Route planning and guidance

28 Intelligent Mobility Applications Inform driver when blind pedestrian is waiting at an intersection Warn blind pedestrian not to enter crosswalk where there is potential red light runner Extend pedestrian phase for registered blind, elderly, or disabled people Connected Vehicles Initiative (V2I, V2P, P2I)

29 Thank You! Chen-Fu Liao Minnesota Traffic Observatory Department of Civil Engineering University of Minnesota (612)