|
|
|
 |
 |
Description A speech message is provided during the Walk interval, usually from a speaker located at the pushbutton, which states something like: 'Maple Street, WALK sign is on to cross Maple.' Basic issues Some systems have the capability of utilizing directly audible speech messages to provide information about the status of the signal cycle. As for other WALK indications, the speech WALK message must be detectable, localizable, and recognizable. For use as a WALK indication, a speech message must also be correctly understood by all users. The following sections discuss some issues and problems to be considered in the use of directly audible speech messages:
MUTCD provides minimal information regarding speech WALK messages. It states that: "The verbal message that is provided at regular intervals throughout the timing of the Walk interval shall be the term " WALK sign," which may be followed by the name of the street to be crossed" (MUTCD 4E.06). Associating speech messages with street to be crossed Speech messages from pushbutton integrated APS seem very user-friendly and have become popular in the US market. Such messages can communicate to all pedestrians which street has the Walk interval. However, the words and their meaning must be correctly understood by all users in the context of the street environment where they are used. Use of speech messages will not automatically solve all ambiguity problems that were discussed earlier in this section. Draft Public Rights-of-Way Accessibility Guidelines allow the WALK indication to be provided by 'voice' but do not provide additional specifications. PROWAAC recommended the use of a speech WALK message to clarify to which crosswalk the signal applies, if signals for two directions cannot be separated by more than 10 feet (X02.5.1.3G). Need to know street name Pedestrians have to know the names of streets they are crossing in order for speech WALK messages to be unambiguous. In getting directions to travel to a new location, travelers do not always get the name of each street to be crossed. They may only know that they have to cross four streets before looking for their destination. Therefore, the APS has to give the user the name of the street controlled by the pushbutton. This can be done by means of a pushbutton information message during the flashing or steady DON'T WALK intervals. (See pushbutton information messages.) Cognitive complexity Most APS that can provide speech WALK messages, can also provide a pushbutton information message that clarifies which street the pushbutton and signal controls. In addition, they may have the option of Braille labels. The user must combine the information from the pushbutton information message or Braille label, the tactile arrow, and the speech WALK message, in order to correctly respond to the WALK messages, particularly if there are two pushbuttons on a pole. All may be necessary to correctly identify the street and crossing time at an unfamiliar intersection. This complex process is much more cognitively demanding and liable to result in errors than the simple system adopted decades ago in Australia and several European countries, in which the source of a WALK tone is in the immediate vicinity of where pedestrians are standing to initiate the crossing associated with that tone. Which street should be named? A survey of travelers who are visually impaired, orientation and mobility specialists, and transportation engineers (Report on Speech Messages, Bentzen et. al., 2002) noted a difference in 'naming' of streets in speech messages. A message stating "Howard Street, WALK sign" was generally understood by engineers to indicate that the WALK sign was on for traffic traveling alongside Howard Street, while pedestrians who were blind or visually impaired and orientation and mobility specialists consistently interpreted it to mean that the WALK sign was on to cross Howard Street. WALK messages must contain the name of the street being crossed, or they may lead to misinterpretation by pedestrians who are blind or visually impaired. Recommended messages are included in the section on Model messages in this page. Understanding speech in noise Most APS currently available deliver the message from a speaker located at the pushbutton. Locating the APS speaker as close as possible to the crossing location is desirable. Most pedestrians with visual impairments also have some degree of age-related upper-frequency hearing loss, limiting their understanding of speech in traffic conditions. It will not be possible to make speech messages from APS loud enough to be intelligible in all ambient traffic conditions by most people unless they are also loud enough to potentially cause hearing loss in people in the immediate vicinity of the loud speakers. In even moderate traffic conditions people who have age-related or other hearing losses, people who are not native English speakers, and people with cognitive disabilities are likely to miss hearing or to misunderstand some words, possibly resulting in misunderstanding entire messages. In locations where speech messages have been broadcast from a pedhead-mounted speaker, there has been difficulty making the speech information intelligible in the presence of traffic sounds. Increasing the volume of a speech message so it can function as an audible beacon is likely to result in decreased intelligibility of the speech message. Conveying necessary information Speech messages need to provide accurate information in a clear, concise, and standardized manner, so pedestrians will know what to expect from the messages and be more likely to understand them.
Model messages Speech messages for the Walk interval of directly audible APS should follow these model messages (Bentzen, Barlow and Franck, 2002).
Recording messages To be understood, speech messages must be carefully recorded, in a clear voice, with excellent diction, and moderate pacing. There is no clear preference between use of a male or female voice. For persons with unimpaired hearing, a female voice will be understood somewhat better than a male voice because the frequency spectrum of the male voice is closer to that of traffic. For the large number of people who are visually impaired who also have age-related or other upper-frequency hearing loss, a female voice may not be as easy to understand as a male voice. Maintaining signals with speech messages Replacement of signals having speech messages necessitates custom recording rather than off-the-shelf substitution of components. The speech message, as well as the associated pushbutton message or Braille label, is intersection and crossing specific. Manufacturers of APS with speech messages can provide replacement message 'cards' or provide software for the installer to record the speech messages. Care must be taken in the installation and/or replacement of signals to assure that the street name in any WALK message is the name of the street being crossed. top 
|
|
| << previous page | next page >> |
 |
This site
was developed under the sponsorship of the National
Cooperative Highway Research Program. |
