APS Guide Overview

Chapter 1: Introduction

Chapter 2: Travel by Blind Pedestrians

Chapter 3: Understanding Traffic Signals

Chapter 4: Features of APS

Chapter 5: When to Install APS

Chapter 6: Designing APS Installations

Chapter 7: Installation & Operation

Chapter 8: Public Education

Chapter 9: U.S. Case Sudies

Chapter 10: International Case Studies

Appendix A: Current Guidelines

Appendix B: Product Information

Appendix C: Research on APS

• Research on problems of blind pedestrians
• Effects of APS on particular street crossing tasks
• Effects of APS on independence and confidence
• Effects of WALK signal characteristics
• Accuracy and speed in identifying WALK indication for a given crossing
• Research on source of the WALK signal
• Research on other APS features
• Other concerns and needs
• Need for additional research
• References

Appendix D: Prioritization Tool Instructions and Forms

Appendix E: Glossary

References

Resources

Abbreviations

Effect of APS on independence and confidence

Both independence and confidence affect the likelihood that people who are blind will cross streets independently. Lack of independence and low confidence in ability to cross safely result in lack of participation in normal community life.

Independence

Both the NEI research and earlier SKERI research on which the method was based measured independence on three street-crossing tasks both with and without APS: locating the crosswalk; starting to cross within the WALK interval; and completing the crossing. The NEI research also measured independence on aligning to cross. The percent of crossings on which participants were independent on each task is as follows.

Task	Without APS		With APS
	SKERI	NEI	SKERI	NEI
Locating crosswalk	81%	81%	99%	95%
Aligning to cross	NA	94.5	NA	97%
Starting to cross during Walk	76%	79%	100%	92%
Completing the crossing	81%	86%	97%	96%

Table C-1. Percent of crossing tasks on which participants were independent.

Confidence

Marston and Golledge (2000) measured confidence in street crossing with and without APS. The range of responses for the no APS condition, by street crossing task, was 2.7-3.5 (5 pt. scale; 1=no confidence, 5=very confident), while the range of responses by task for the APS condition was 4.8–5.0.

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