by Penny Reeder
(Based on the research report by Beezy Bentzen, Janet Barlow and Lukas Franck, available soon online at http://www.acb.org)
Introduction
Many people who are blind and visually impaired have been pleased to find traffic engineers more likely than ever before to install accessible pedestrian signals (APSs) at intersections where information about when the walk interval begins is routinely disseminated to sighted pedestrians with a visual display from a Walk/Don't Walk sign. An accessible signal is an augmentative device, i.e., reliance on an accessible signal does not obviate the necessity of focusing on the situation at hand, using all of one's senses and relying on good orientation and mobility techniques for crossing streets.
The accessible pedestrian signals of today have come a long way from the beeping and chirping/cuckooing signals of years past. Many blind and visually impaired pedestrians appreciate the spoken messages which the newer signals can deliver, not merely concerning when the walk signal is on to cross a given street, but also identifying the intersecting streets, and sometimes delivering additional information as well. Yet, the diversity of messages can in itself become confusing.
Research was conducted, under a grant from ACB and the California Council of the Blind (CCB), with additional assistance from the Seeing Eye, the Center for the Visually Impaired in Atlanta, and the U.S. Access Board, to determine exactly what types of messages are most helpful to blind pedestrians, and when spoken messages should, in fact, be utilized at all. The results of this research include recommended "model" messages for use during different parts of the signal cycle. Two model messages are recommended for use during the walk interval, i.e., the part of the signal cycle when the pedestrian signal shows "WALK" or a walking person, to indicate the segment of the cycle when pedestrians can start crossing the street. A number of model messages are also recommended for use during the flashing don't walk and steady don't walk intervals, the parts of the cycle when pedestrians should not begin a crossing. These messages are referred to as "pushbutton messages" because they come on when you push the button, either immediately, or after holding the button down for a few seconds. They give more information about the intersection such as which crosswalk is controlled by that pushbutton, and information about unusual signalization or geometry at the intersection.
The research report also includes a cautionary section in which the authors discuss their reservations about whether providing spoken messages is an appropriate methodology for making the pedestrian signals accessible to the majority of blind and visually impaired pedestrians in all situations. One factor which leads to their reservations is that many older blind people have age-related hearing loss. They can usually understand a male voice better than a female voice, but a male voice has frequencies that are more like those in traffic than a female voice. So, if the messages are recorded by a male voice, older blind people may be able to understand them in very quiet situations but not when there is traffic, because the traffic sound can mask the speech. However, if the messages are recorded by a female voice, which younger people can understand more easily when there is a lot of traffic noise, older people can't understand them just because the voice is too high. It's a real catch-22, and it may be necessary to engage in additional research to identify alternative sound-generating mechanisms for alerting pedestrians about the onset of the walk interval.
Background
Recently, APS that provide audible information from the pushbutton location have been introduced in the U.S. This type of signal has been used extensively in Europe and Australia for many years. These signals typically use a rapidly repeating tone to indicate the walk interval, and a slower repeating tone during the "flashing don't walk" and steady "don't walk" intervals. The slowly repeating tone alerts users to the need to press a button to request a walk signal, and helps users locate the pushbutton. Vibrotactile information is also provided by most of these signals. In the U.S., in some of these pushbutton integrated signals, spoken messages are being used to indicate the walk interval information, as well as additional information about the names of applicable streets, the geometry of the intersection, etc.
Many blind and visually impaired people consider the signals which provide spoken messages to be very user friendly. During last year's deliberations of the Public Rights-of-Way Access Advisory Committee (PROWAAC), representatives of the American Council of the Blind, the National Federation of the Blind, the Council of Citizens with Low Vision International, the Association for Education and Rehabilitation of the Blind and Visually Impaired, and The Seeing Eye all supported the use of APS which can deliver speech messages, to reduce possible ambiguity about which crosswalk has the walk signal at certain intersections, especially intersections at which there are two pushbuttons mounted on the same pole.
Currently there is minimal standardization of walk messages and pushbutton messages for APSs. Therefore message content, length, and structure can and do vary considerably from one APS installation to another. The only existing standard for the wording of APS speech messages is contained in the Manual on Uniform Traffic Control Devices (MUTCD) which was published early in 2001. This standard requires that where verbal messages are provided during the walk interval, "the verbal message . . . shall be the term 'walk sign,' which may be followed by the name of the street to be crossed," and the verbal message during the flashing don't walk and don't walk intervals "shall be the term 'wait.'"
Although some preliminary research about the content of spoken messages was conducted under the auspices of the Smith- Kettlewell Eye Research Institute in 1996, there remained a need for research to identify the structure and content of spoken messages which blind and visually impaired pedestrians find most useful.
Methodology
An expert panel met by teleconference to develop a survey to be given to stakeholders, including pedestrians who are visually impaired, orientation and mobility specialists, transportation engineers, and accessible pedestrian signal manufacturers. Members of the expert panel were Billie Louise Bentzen, Janet Barlow, and Lukas Franck, (all of whom are certified orientation and mobility specialists), and one representative familiar with speech equipped APSs from each of the following groups: transportation engineers, APS manufacturers, Council of Citizens with Low Vision International, and the American Council of the Blind. The National Federation of the Blind declined the invitation to participate in this research.
The Messages
The expert panel developed sample walk interval and pushbutton messages that were applicable to different intersection geometries and signalization patterns, and that varied in message content, length, and structure. Each message approved by the expert panel was required to have consensus that it was appropriate in content and structure. Appropriate messages were those that were judged by most expert panel members to be unambiguous, and to clearly convey the minimum necessary information.
Expert panel members held extensive discussion about safety concerns related to the wording of the walk and pushbutton messages. It was considered essential that the wording of a walk message should indicate the status of the signal, neither giving a command nor implying that it would be safe to cross. The researchers were mindful that misunderstanding messages could place pedestrians in life-threatening situations, so they eliminated from consideration any message they thought could be misinterpreted if a person missed hearing or had difficulty hearing part of it.
There was concern that some messages that have been used as pushbutton messages, that is, coming on during the flashing or steady don't walk intervals, such as "Crossing Charles at State," could be misinterpreted as a walk message by a pedestrian unfamiliar with such messages. This discussion led to the decision that the words "crossing" and "walk sign" should not be included in pushbutton messages. There was also discussion of the words "to cross." The panel decided that "to cross" could be used as part of a phrase in the pushbutton message, but not at the beginning of the message. If used at the beginning of a message, if the word "to" is not heard or understood, pedestrians could mistakenly understand that "cross" means they should cross now.
The expert panel also decided that the word "wait" should be included in every pushbutton message, because pushbutton messages always come on during either the flashing or steady don't walk intervals when pedestrians should, in fact, be waiting. The panel discussed the types of information to be provided by the pushbutton messages at length. While there was recognition that APS could provide landmark and construction information, the panel decided that APS should be used to provide only crossing and intersection information. That is, the APS should be a pedestrian signal only. The separation of traffic signal information from other types of information was considered a safety issue. The panel felt that other types of information should be provided by other means.
Messages selected by the expert panel were developed into a survey instrument for determining which information was preferred by blind travelers, orientation and mobility specialists, transportation engineers, and APS manufacturers. The survey also contained items to evaluate how well various types of information were understood and a question to determine users' preferences about whether the pushbutton messages should come on immediately versus after holding the pushbutton down for a few seconds.
The survey was administered in braille, large print, or orally to 170 pedestrians with visual impairments who were attending the convention of the American Council of the Blind in Des Moines, Iowa, during the first week of July 2001. The same survey was mailed to 160 people who are actively involved in decision-making about pedestrian signals or in teaching pedestrians with visual impairments to recognize and interpret the geometric and signal information at intersections, including orientation and mobility specialists, APS manufacturers and distributors, and transportation engineers.
The panel reviewed the survey results via a conference call and made recommendations based on the results and comments collected.
Conclusions
The expert panel recommended the following model messages for specific situations, based on the results of the survey and their own expertise. Further, they recommended that all installations should be developed on the basis of these models. They recommended that the structure and content of actual messages should follow the models as closely as possible. Word order should not be changed. Where complete sentences are used in the models, they should be used in actual messages for the same situations. Where sentence fragments are used in models for other situations, they should be used in actual messages for those situations. In the model messages, such words as street, avenue and road are not used except for locations where they may be needed to avoid ambiguity. Model Walk Interval Messages: messages that could come on when the walk sign is on.
It is important to point out that understanding the content of a walk interval message is crucial. It can be life-threatening to misunderstand what one of these spoken messages means. It's essential that the user understand which street the walk message applies to.
So, here is the recommended model message for the walk interval, applicable to most intersections: "Howard. Walk sign is on to cross Howard."
Here is a model walk message for intersections where all vehicles have a red light during the walk interval, and all crosswalks have the walk sign at the same time: "Walk sign is on for all crossings."
Model Pushbutton Messages
Pushbutton messages can come on during either the flashing or steady don't walk intervals when the button is pushed. They either come on immediately or after about a three-second button push. The content of pushbutton messages, while helpful to pedestrians, is not of crucial importance in terms of life safety. The pushbutton message provides street names, intersection geometry, or signalization information. If the pedestrian doesn't understand the pushbutton message the first time, it's possible to play it again.
Here is the basic recommended model message for pushbutton intersection identification: "Wait to cross Howard at Grand." This message means that you should not start to cross because it is either the flashing or steady don't walk interval, and that you have pushed the button to request a walk signal to cross Howard Street, and Grand is the street beside you.
Other model pushbutton messages include information about signalization or geometry as well as intersection identification. A model pushbutton message for intersections where all vehicles have a red light during the walk interval, and all crosswalks have the walk sign at the same time and no right turns on red are permitted is: "Wait to cross Howard at Grand. Wait for red light for all vehicles."
A model pushbutton message for intersections where all vehicles have a red light during the walk interval, and all crosswalks have the walk sign at the same time but right turns on red are permitted is: "Wait to cross Howard at Grand. Wait for red light for all vehicles. Right turn on red permitted."
A model pushbutton message for angled crosswalks is: "Wait to cross Howard at Grand. Crosswalk angles right."
A model pushbutton message for crosswalks to medians where a second button push is required is: "Wait to cross Howard at Grand. Short walk phase. Raised [or cut-through] median with second pushbutton."
A model pushbutton message for signalized crosswalks to splitter islands is: "Wait to cross right turn lane to island for Howard and Grand crosswalks."
A model pushbutton message for crosswalks at "T" intersections is: "Wait to cross Howard at Grand." Note that this is the same as the basic pushbutton message.
The expert panel recommended the following order of information for pushbutton messages:
- Intersection identification;
- Intersection signalization (if remarkable); and
- Intersection geometry (if remarkable).
The expert panel concluded that pushbutton messages should come on after a long button press. Currently the length of this extended button press is about three seconds; this will be standardized in the future based on research, and is expected to be less than three seconds.
If the decision is made to use APS with speech messages at a particular intersection or crosswalk, the messages should be worded carefully, according to the models above, or the nearest approximation to the special situations in which they will be used. The messages then must be recorded very carefully, in a clear, moderately pitched voice, with excellent diction and moderate pacing. Cautions Expressed
Those interested in speech messages should be aware of some of the concerns raised in this report regarding the difficulty of providing speech messages that will be clearly understood by all users. It is not likely to be possible to make speech signals understandable in all ambient noise situations such as loud traffic, and it is easy for listeners to miss or mistake parts of messages in loud ambient noise situations. Non-English speakers and non-native English speakers are likely to have difficulty understanding speech messages. To be understood, speech messages must be carefully recorded, in a clear voice, with excellent diction, and moderate pacing.
For all of these reasons, the researchers came to question the premise that spoken messages are the best way to present information about when it is safe to initiate a pedestrian crossing. Further, the researchers believe that generating other kinds of sounds may be a more appropriate way to communicate with a larger segment of the population, since it is relatively easy for a large number of people to mis-hear the content of spoken messages. Further research should be conducted to identify the kinds of sounds which may contain the least possibility for ambiguity. Sound systems which incorporate a location factor which can serve as a beacon may be investigated by this and other research teams. Follow-Up Research
The authors of the report accompanied several ACB staff members on a visit to installations of APS with speech messages in the Baltimore/Washington area in January of this year. We discovered that some of the messages were ambiguous and hard to understand. Where two pushbuttons were on the same pole, and the pole was more than 10 feet away from the crosswalk, it was difficult to understand the walk messages. This was a situation in which it was absolutely essential that the messages be understood because a blind pedestrian had no way to know which crosswalk had the walk interval. Where pushbuttons for two crosswalks were on two separate poles at a corner, it was pretty easy to tell which crosswalk had the walk interval because you could hear that the sound was coming from the pushbutton you had just pushed. You didn't really have to understand what it was saying; you just knew from where it was that it was the signal you were waiting for.
Those visits provided additional information to those of us who had previously believed that spoken messages were the best, perhaps the only way, to provide unambiguous information about when it is safe to initiate a pedestrian crossing. Where the APS are separated by a minimum of 10 feet, as recommended by the Manual on Uniform Traffic Control Devices, it seems like it isn't absolutely essential to understand exactly what the spoken messages are saying to tell which crosswalk has the walk interval. It's only where two pushbuttons are on the same pole that speech messages are needed for walk interval messages as recommended by PROWAAC. It seems like the additional information available in pushbutton messages is a good idea regardless of whether APS are on the same or separate poles, but utilizing spoken messages to convey the walk signal information may not be as good as having tones, so long as the pushbuttons are separated.
According to Bentzen, Barlow and Franck, having very consistent placement of pushbuttons at or very close to the end of the crosswalk, and within about three feet of the street makes APS that just have locator and walk tones extremely effective in countries such as Sweden and Australia where they have been common for many years. Bentzen says, "You can find a pushbutton using the locator tone, push it, and be sure you are waiting in exactly the right place to align for a crossing, and know that a very short distance into the street you will hear the locator tone from the APS on the other side or on the median, and you can home in on it as you cross the street."
Standardization of pushbutton location in the US is now a hot topic in the US Access Board, the National Committee on Uniform Traffic Control Devices, and the Federal Highway Administration. ACB advocacy will be needed to achieve standards for consistent pushbutton placement. This is seen as something that is good for all pedestrians: put the button where it's needed, not 20 feet away, behind the fence!
Meanwhile, if you're requesting an APS, don't just assume that your local traffic engineer will know what message it should have and where it should be located. Follow up every step of the way! The best equipment can provide useless, or even dangerous, information, if not well installed. If you think it would help you to have the assistance of an O&M specialist who is knowledgeable about APS issues, ACB can put you in touch with the member of the AER Environmental Access Committee for your area who is especially prepared to provide technical assistance. Call the ACB national office, (202) 467-5081, or go to the list of Enviornmental Access Committee members posted at http://www.aerbvi.org/Division9/ea.htm.