Interfaz  de  usuario

It is very important to understand what people with visual impairments need from an APS system as they are the targeted users. To help us with this understanding, we conducted a group interview with the help of our liaison at Dansk Blindesamfund, John Heilbrunn. A detailed summary of the group interview can be found in Appendix E. The following is a summary of the topics that were discussed and the reactions of the group.

Demographics

To begin with we wanted to know some of the demographics of the people that we were interviewing. It is important to keep the answers in the perspective of the background of the individuals providing the answers. In this case, there was an even distribution geographically.

Of the nine participants, three were from the Copenhagen district of DBS, three were from the Frederiksberg district and three were from the northern suburbs of Copenhagen. Representing a wide geographic distribution was important because APS vary by area and municipality.

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We also wanted to track the age distribution of interviewees. However, this was not necessarily representative of the age distribution of those people who spend the most time independently navigating. While a sample size of nine people that were not randomly selected is not necessarily representative of this population, it was also important to know the age

distribution to allow us to keep a perspective of the answers given. For example, during our background research, we discussed with both Bentzen and Raymond that older people might be more hesitant to adopt new technology. Therefore answers to questions about new technology would have to be taken into perspective based on the age distribution of the interviewees. Of the nine individuals, five were between 25 and 44 years old, three were between 45 and 64 and one was over 65. This age distribution is not representative of that of blind people in Denmark because the majority of people with visual impairments are older. However it still covers a wide range.

We also wanted to know how mobile our interviewees were. Every person present used a white cane. Three people used guide dogs to navigate. Each one was a well experienced

independent traveler who often navigated the city on foot, by bus and by train. Many traveled for work as consultants for the DBS. The interviewees well represented the blind population that would use APS the most frequently and might often travel in unfamiliar areas. However, this did not cover the entire spectrum of potential users of the system.

Crossing the street

Everyone who was interviewed said that they benefit from using APS when they are functioning correctly. Many problems make crossing more difficult such as crossing streets that do not intersect at right angles. Wind can play havoc on crossing for many reasons. Wind can make sounds drift away from the pedestrian. Also, if there is wind in the pedestrian’s ears, the sound can cover up important sounds that are used to determine when it is safe to cross. Often, if the intersection is deemed too hazardous, due to either it being a complex intersection with no APS or if the APS is not functioning correctly, the pedestrian may ask for help from a sighted person at the intersection. Danish law allows 15 hours of guide time per month for a variety of purposes, such as when they must go to an unfamiliar area. This is an important part of

Denmark’s social service program.

DWS and tactile pathways

Of the nine interviewees, eight found DWS to be helpful where it was present. The ninth interviewee had diabetes which prevented him from feeling textures under his feet and

therefore did not find the DWS helpful. The most common type of tactile path in Copenhagen is

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the line of cobblestones found in the center of a most sidewalks, which can be seen in Figure 14.

These can be differentiated from the regular cement pavers on either side of the cobblestones.

Specific tactile paths are used frequently around train stations or for crossing large open squares. At least one interviewee found that bars were much easier to feel than dots or

truncated domes. One problem with tactile paths that do exist is that sometimes hotdog stands or other street vendors will park right over the top of the path. Also, some places in the city have historical restrictions that prevent the installation of the rubber or metal tactile pathways.

Figure 14: A typical Copenhagen sidewalk outfitted with Detectable Warning Surfaces (DWS)

APS

Everyone found the APS signals to be very helpful when they can be heard. Some

examples of unhelpful implementations include some places in Norway where the locator signal is turned off and only the crossing signal plays. This is not helpful for pedestrians trying to find the APS device before crossing. Another problem is with devices that do not have a locator tone and require a button press to either activate the APS or even to activate a pedestrian phase.

Without any locator tone, there is no guaranteed way to find the device to push the button. In Frederiksberg, one intersection must be activated by a button press, but there is a constant locator tone. Also, the interviewees understand that sometimes it might be appropriate to turn down the volume of a signal during the night, but they all agreed that turning off a signal was unacceptable as this meant they were limited to travelling only during the day if they were not comfortable crossing streets without the signals to guide them.

There were many opinions on what was best for the sound of an APS. Most people agreed that the knocking sound used in Frederiksberg was easier to hear over the noise of traffic. There

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was also an interest in spoken messages because of the extra information that they would provide, but it was also realized that excessive amounts of information could take away from the concentration necessary to guarantee a safe crossing. Some people believed that a sound with more frequencies would be easier to hear for a wider variety of people and can improve people’s ability to locate the source of a sound.

Tactile arrows are a very important part of the whole system and are very helpful for orientation if they are installed correctly. If one cannot hear the opposing signal to navigate toward, the tactile arrow is the only means of orienting in the correct direction for crossing. If the arrows can be moved, they actually pose a safety hazard. Tactile maps had been heard of by a few, but only one had been encountered near Copenhagen. Some people believed it would be nice to have more information, such as whether or not there is a bike lane. However, it was also noted that information would have to be concise and easily understood to prevent confusion.

Maintenance has been a constant issue with the devices. Malfunctioning systems are reported quickly by the people who use them. However, the interviewees said that the response time varied from a few days to weeks. There were also experiences of conflicts with neighbors where the neighbor might call to have the signal turned down which would be followed by the blind pedestrian calling to have the volume increased.

The main comment on user centered systems was that pedestrians should not be required to use another device. Many people with visual impairments describe a “gadget hell” in which there is a specific device to help with each of a number of specific tasks. Carrying around many different devices for many different tasks becomes more difficult as the user must keep track of where the device is, identify it in relation to other devices, and keep track of which devices need charging.

Suggested solutions

For those who are both deaf and blind, the vibrator on a cell phone could be used to indicate crossing signals. Traffic islands could also be more identifiable to let users know that they are in a safe location. For example, the cut in a median could be slightly raised or use a different material than the rest of the crosswalk. Another solution proposed would be to have a Bluetooth based system incorporated in the user’s cell phone. A program on the cell phone would be able to trigger the APS device and indicate any special needs that the particular individual might need. Examples of needs might be a higher signal volume, different frequencies that are easier to hear, or a longer crossing period.

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