The Smith-Kettlewell Eye Research Institute
Rehabilitation Engineering Research Center
2232 Webster Street
San Francisco, CA. 94115
March 15, 1995

Transit Accessibility Improvement through Talking Signs® Remote Infrared Signage:


A Demonstration and Evaluation
William Crandall, Ph.D.
Billie Louise Bentzen, Ph.D.
Linda Myers, M.Ed.
Philip Mitchell, Ph.D.

This report was developed with assistance derived from the Federal Transit Act, as amended, through a Cooperative Agreement with the U.S. Department of Transportation, Federal Transit Administration and Project ACTION of the National Easter Seal Society.

Foreword

This technical report is one of three documents that resulted from the project entitled "Transit Accessibility Improvement through Talking Signs® Infrared Remote Signage: A Demonstration and Evaluation" (W. Crandall, Smith-Kettlewell RERC) funded by Project ACTION. The main activity of the project was installing Talking Signs® in a tri-level transit station in San Francisco and testing their effectiveness in providing wayfinding information to people who are visually impaired.

This Technical Report sets out the need for accessible signage for people who have print reading disabilities, and discusses why Talking Signs® remote infrared signage is the technology of choice (within the context of previous human factors studies). Finally, it provides the rationale for and the results of studying the impact of training on the use of the technology in a complex transit facility. The project's two companion documents are: Bentzen, B., Myers, L., and Crandall, W. " Talking Signs® System: Guide for Trainers." Project ACTION, 1995 and Crandall, W. "Talking Signs® Remote Infrared Signage: A Guide for Transit System Managers." Project ACTION, 1995.

The activities of this project were guided, in part, by a Steering Committee comprised of administrators of agencies providing services to blind persons, blind persons who regularly use public transit, and the accessibility officials from the San Francisco Municipal Railway (Muni), and the Bay Area Rapid Transit (BART). At the conclusion of the project, the Steering Committee unanimously approved the following final recommendation to be presented to Project ACTION.

"Having noted that the Talking Signs system enables users who are print handicapped to travel independently throughout a complex transit station, that even users who receive minimal training benefit from this system, and that transit operators experienced no operational hardships as a result of this system, we recommend that remote infrared audible signage (specifically Talking Signs®) is the preferred technology enabling print handicapped persons to travel independently in transit facilities."

1. Introduction

Rationale:

Effective mobility depends upon proper orientation; for mainstream society this is accomplished by printed signs. People who are print disabled, are blind, or have other visual impairments are at a disadvantage for the lack of labels and signs. For sighted travelers, signs provide identification and directions. In the broadest sense, signs comprise a menu of choices for travelers; they confront them with the options available at any given point in their travels. In a sense, signs act as a form of memory for travelers; signs "remind" travelers about important characteristics of the environment.

Currently, persons with severe visual impairments most often require extensive assistance from strangers in order to travel in unfamiliar areas. In the best case, the information they receive is accurate, concise, and in the appropriate language. Such an ideal source of information is seldom available. In urban areas, persons who are blind may have safety concerns about approaching strangers for assistance. Finally, blind people just do not like to be dependent upon others for information -- especially if there are suitable alternatives.

The National Center for Health Statistics estimated that 4.3 million people in the US have difficulty reading the newspaper with their corrected vision -- a functional definition of perceived limitations termed Severe Visual Impairment as defined by Nelson and Dimitrova in the American Foundation for the Blind's Journal of Visual Impairment and Blindness of March, 1993. Importantly, an additional 2.3 million people have a disability that involves the loss of intermediate or distant vision only. From these statistics, we may conclude that a total of 6.6 million people are unable to read printed signs at normal viewing distance. Data from the Bureau of the Census put the figure for this same level of impairment at 9.7 million people (McNeil, 1993). There is another important way of looking at the demographics of blindness. Estimates of tested acuity classify 1.1 million people as Legally Blind which is defined as corrected acuity of 20/200 or less and a visual field of < 20 0 (Chiang, et al, The Milbank Quarterly, Vol. 70, No. 2, 1992).

Many other disabilities prevent persons from reading print. In addition to people who are blind or have low vision and may not be able to see the print, there are many stroke, head-injured, autistic and dyslexic (or even just educationally impaired) persons who may not be able to assimilate printed language even though they can see the page. Many people can accept this information through speech -- having print read aloud to them.

Remote Infrared Signage:

Remote infrared signs allow people who are print disabled to directly know not only what, but where. Just as non-disabled people visually scan the environment to acquire both label and direction information, remote infrared signs directly orient disabled people to the labeled goal and constantly update them as to their progress to that goal. That is, unlike Braille, raised letters, or voice signs which passively label some location or give instructions to some goal, the remote signage technology developed at The Smith-Kettlewell Eye Research Institute (Talking Signs®) provides a repeating, directionally selective voice message which originates at the sign and is transmitted by infrared light to a hand-held receiver some distance away. The directional selectivity is a characteristic of the infrared message beam; the intensity and clarity of the message increases as the sign is "pointed at" or approached. This ensures that the people using the Talking Signs® system can choose to get feedback about their relative location to the goal as they move towards it. Talking Signs® are light and small, easy to install, consume very low power, and are easy to program with human voice or synthesized voice messages. Talking Signs® conform to the ADA guidelines which stipulate that an accommodation must also be "refusable" [Title V, sec. 501(d) ADA] Talking Signs® has been subjected to rigorous human factors testing in several settings as reviewed below (see "Background").

Figure 1. The infrared message beam is directional. By scanning the receiver around the environment, the user is able to determine the precise direction of each of the signs.


Purpose of the Present Study:

Transit stations present unique challenges to people who are print disabled; they must visit specific points along potentially crowded and complex paths of travel having no signs which are legible to them, in order to successfully navigate from street entrances to the proper train. Such a course involves the challenge of identifying the correct entrance, change and ticket machines, station agent kiosks, entry gates, escalators, steps and elevators onto the platform, a specific platform area and specific train or coach.

This project details a transit station installation in which we developed, tested, and determined acceptable performance levels for the Talking Signs® wayfinding technology. In addition, we sought to determine the appropriate level of training for users of this wayfinding system.

Previous research indicates that Talking Signs users independently learned many characteristics of the system which we did not specifically teach them in the short training preceding test trials. Ease of use, learning to scan, ease of picking up messages, and following the sign to the destination are thought to be related to the level of training and indicate a need to evaluate training requirements for effective and safe use of Talking Signs. The present study, therefore focused on the question: "What is the minimum amount of training required for a person to effectively and safely use the Talking Signs system?" To answer this question, we evaluated the travel characteristics of 36 visually impaired people who used the Talking Signs system as an aid to navigation through a complex subway station in downtown San Francisco (Powell Station) for the Bay Area Rapid Transit (BART) and the San Francisco Municipal Railway (Muni). The broad cross section of subjects was divided into three groups, each group being matched for varying levels of mobility skills, degree of residual vision, and method of travel (guide dog or cane), presence of hearing impairment, and level of spatial thinking. Each group received a different level of training on the proper use of the system.

Collaboration:

The collaboration between Smith-Kettlewell Eye Research Institute, the Living Skills Center (for orientation and mobility training) and Dr. B. L. Bentzen of Accessible Design for the Blind (for the human factors evaluation), BART and Muni presents a unique opportunity for rehabilitation engineering, human factors research, Orientation and Mobility (O&M) specialists and transit providers to make a significant and timely contribution to moving accessibility technology into the public sector.

2. Background

Audible Signage: Available Technologies: The disability community has had significant experience with audible technologies in the form of Assistive Listening Devices for the hearing impaired. The Architectural and Transportation Barriers Compliance Board (ATBCB) pamphlet entitled Assistive Listening Systems lists four technologies currently in use and the advantages and disadvantages of each technology for this application. These include amplitude modulation (AM) and frequency modulation (FM) radio, inductive loops (magnetic) and infrared (light). Additional experience has been gained in using some of these technologies to serve the general public as tour information systems in museums.

A number of specific applications of audible signage for persons with visual deficits have either been proposed or fabricated. Two examples of proposed systems have been put forward by the College of Communications at California State University at Chico and NYNEX Science and Technology, Inc.

The proposed Chico system would label strategic places of interest with radio frequency transmitter/receiver devices. The user carries a personal receiver/transmitter device which would both "trigger" and receive a code from the remote label. Internal to the personal receiver is a decoder and voice synthesizer to convert the label information into speech output (Main, R., 1991). A disadvantage of this system is that it is non-directional. A directional audible signage technology has proven superior to a non-directional system in human performance testing with people who are visually impaired (Bentzen and Mitchell, 1995).

The proposed NYNEX system would employ three phases of development. The first would be a "grid" of 20 radio frequency transmitters located on tall structures (each approximately 600 feet in height). The transmitter would broadcast the name of the structure at short intervals. The user would wear headphones to which a directionally selective receiver would be attached and rotate his/her head to locate one or more of these "beacons." If several beacons could be located, the user would "be able to triangulate and ascertain with fair accuracy his/her location and orientation. The second phase involves extremely high frequency, short-range labels (for enhanced directionality) on each street corner. The third phase involves using the global positioning satellite (GPS) system to index geographic information stored in the personal receiver. If speech recognition were added, "the system could respond to user inquiries regarding directions, schedules, and path planning ..." (Urband, E., 1992).

Four audible signage systems which have been tested or produced include designs from the British Open University Interfaculty Electronics Facility, Fanmark Technology Corporation of Auckland, New Zealand, Verbal Landmarks, Inc. of St. Louis and Talking Signs, Inc. of Baton Rouge.

The Open University submitted its talking label-type device for on-campus trials. In this system, the speech emanated directly from an enclosure attached to the location to be labeled. The speech message was "triggered" by the presence of a person in the nearby environment (proximity detector). The researcher considered the advantages of a system that would require a special triggering circuit on the person of the user so that the speaking label would not be constantly activated as members of the (non-disabled) public pass by (Jones, D., 1991). A disadvantage of this system is that all messages such as "Ladies Room" are audible to all passers-by. Audible signage which is audible to the general public has not been favored by blind consumers.

The Fanmark "Locator" employs an FM system that repeatedly transmits digitally recorded human voice messages and uses ordinary, consumer radios tuned to an unused band for the receivers. The technology has the disadvantage of being non-directional.

Verbal Landmark® has an inductive loop system which uses a portable receiver to pick up messages transmitted from an electromagnetic loop. Messages are picked up when the receiver enters the transmission field. The messages are produced by DECTalkR synthesized speech. This technology has the disadvantage of being non-directional.

The Talking Signs® development began at Smith-Kettlewell's Rehabilitation Engineering Research Center in 1978. The infrared system uses light emitting diodes to transmit digitally encoded human speech messages which are picked up and spoken by a speaker in the hand held receiver. The hand-held receiver contains a photodetector at its front end so that the message is detected when the receiver is pointed in the direction of the sign transmitter. Thus, Talking Signs are a directional system whose messages are received only by users and only when users activate their receivers; unwanted information is not heard. Because different signs have different functions, the range and dispersion angle of each sign are adjustable.

Infrared Communication:

The transmission of voice information over light beams was originally demonstrated by Alexander Graham Bell in 1880. The invention, named the Photophone, preceded voice communications by radio by 19 years. It achieved a range of 230 yards within the first year of development. Variations of this invention were employed in both World Wars for use by the militaries of America, Germany, Britain, Italy, and Japan. The German device achieved a range of over eight miles (Hutt, D., et al., 1993.)

Worldwide demand to move steadily increasing amounts of information has led to the reappearance of light, in the form of fiber optic transmission, as the fastest growing communications medium.

In 1978 William Loughborough, an engineer at Smith-Kettlewell's Rehabilitation Engineering Research Center (RERC), experimented with beacons, the idea being to create target-practice and running games for visually impaired athletes. An infrared beacon and accompanying stereo headset was made with which a blind person could precisely align his head position to within several degrees of the beacon.

At this same time, one of the RERC's blind staff members, diverted by sidewalk construction which involved adjacent streets, discovered himself to be lost at a time of night when no one was available to identify the street for him. Even though he is a good traveler with practiced techniques of regaining his orientation, he went through considerable trouble identifying his location.

Experience with the infrared beacons led Smith-Kettlewell's engineers to the conclusion that infrared beams, coded with signage information, could be accessed from a distance, and could be localized using clarity of signal as the criterion. The device was prototyped in 1979 and had its first installation at the Community College in San Diego, California in 1984.

This interest led to psychophysical evaluations of what came to be known as Talking Signs Infrared Remote Signage. Eight research articles and papers have appeared in journals or been presented at meetings important to the field of rehabilitation engineering (Loughborough, W., 1979; Loughborough, W., 1986; Loughborough, W., 1990; Crandall, W., Gerrey, W., and Alden, A., 1993; Crandall, W., 1993) Among these are human factors studies dealing with issues such as the intelligibility of Talking Signs speech output , light emitting diode beamwidth on Talking Signs detection time, and a comparison of two wayfinding technologies (Brabyn, John A. and Brabyn, Lesley A., 1982; Brabyn, Lesley A. and Brabyn, John A., 1983; Schenkman, Bo N., 1986; Bentzen, B. and Mitchell, P., 1995). The system is currently installed in the Center for the Visually Impaired in Atlanta, New York Lighthouse for the Blind, and is currently being installed in San Francisco at the New Main Library, Yerba Buena Park, the City's Public Works Department and numerous street intersections.

Most Recent Research in Audible Signage:

1. The Environmental Access Committee of the American Council of the Blind (ACB) determined that there was enough interest and promise in audible signage as a supplement to tactile signage to warrant a formal, functional evaluation of the two most discussed contemporary technologies (Talking Signs® and Verbal Landmark®). The ACB sponsored a trial of the two systems at its July, 1993 Annual Convention hotel in San Francisco (Bentzen, B. and Mitchell, P. "Audible Signage as a Wayfinding Aid: Comparison of "Verbal Landmarks® and Talking Signs®." 1995). The ACB Environmental Access Committee invited Dr. B. L. Bentzen, a human factors researcher and orientation and mobility (O&M) specialist from Boston College and Accessible Design for the Blind, to design an experiment which would capture the relative strengths and weakness' of each technology in a "real world" situation. ACB Convention participants were considered to be an ideal population to act as subjects for the evaluation because they are generally aware of O&M issues, are from a broad demographic cross-section and, on the whole, are part of the national leadership in their local communities.

Briefly, the results of the ACB study show that Talking Signs has clear performance advantages in both travel time and travel distance over Verbal Landmark. Human performance data showed the "participants who used Talking Signs were significantly less likely to become frustrated and unable to independently complete the route than participants who used Verbal Landmarks." In subjective ratings from the questions and survey, Talking Signs showed significantly better scores than Verbal Landmarks for such items as 1) ease of use, 2) ease of comprehension of message, and 3) desirability in both familiar and unfamiliar areas. In terms of preference of each technology in comparison to no technology, "TS (Talking Signs) was generally considered to increase ease and speed of travel, while the use of VL (Verbal Landmark) was generally considered to decrease ease and speed of travel relative to travel without audible signage."

2. An evaluation of Talking Signs on a campus environment (indoor and outdoor) has recently been completed. An analysis of our results testing the ability of sixteen blind subjects to navigate six routes (six on each of two visits or a total of twelve trials) on the campus of San Francisco State University (Crandall, 1994), indicates that, in addition to other positive outcomes, significantly more routes were successfully completed with the use of Talking Signs (with minimal verbal travel instructions) than without Talking Signs (but with longer verbal travel instructions).

We believe that the results affirmatively answer the question of the efficacy of Talking Signs in wayfinding when compared to verbal travel instructions alone. The subjects' strong desire to carry a receiver with them in both familiar and unfamiliar signed environments (94%) is, perhaps, the best indicator of the perceived benefit of the system as a wayfinding aid. In addition to gaining answers to the specific research questions in that protocol, we gained other insights into issues of "sign" (transmitter) placement, "sign" message content, salience of verbal instructions, subject variability (in terms of individuals' ability to adapt to the new technology) and training requirements.

Other subjective responses to the system included the following: