4.1 Over all finding
The children with cognitive disabilities in this study showed that the SAFEWAY2SCHOOL system is as useful for them as for other children. This finding suggests that the system has, in fact, successfully adopted the “design-for-all” concept [14]. Despite the fact that the CWD in the present study all had cognitive disabilities affecting their intellectual capacities, they were able to not only notice, realise and understand the system, but also trusted and accepted it. From these aspects there were no differences between the two groups.
4.2 Understanding
However, when it came to knowledge and how best to act, there was one single difference between the two groups. Albeit the fact that in four of the five video scenarios both groups scored equal, what to know and do in the Go home scenario was the divider between them. The CWD scored nil on what to know and do and negative on what they saw in that video scenario. As a matter of fact, so did they Con group as well, with respect to what they saw, but not to the same extent. It appears that this particular scenario was associated with a larger proportion of erroneous responses than the other four across the groups. Knowing that the typical traffic injury event affecting school children happens on the way home from school, with the child running out behind or in front of the school bus and being hit by oncoming cars [13, 20], this finding is alarming. However, further scrutiny of the responses revealed that both groups did actually understand the SAFEWAY2SCHOOL system’s functionalities, but did not set that knowledge into context of that particular scenario. Why this was the case remains unknown. It could simply have been an effect of how the scenario was filmed or a fatigue effect among the participants based on the fact that several of the statements were quite similar but just adapted to each specific video scenario. Regardless, the last leg of any return school bus trip is the most risky one [8, 21], and this message should come across to the children utilising the system, as well as to parents, bus drivers, other road users and stakeholders.
4.3 Visual scanning patterns
The children’s visual scanning patterns were almost identical, the only differences being a higher number of fixations on three objects. However, all of them were only of medium effect sizes. With respect to fixation durations, no differences were found. Longer fixation durations are known to occur when an object is hard to recognise (bottom-up processing) or when it is of great interest (top-down processing) [22–25]. Given the design of the study, in which participants viewed the videos for the first time without knowing what to expect, except for the features presented in Fig. 2, a certain element of bottom-up processing could be anticipated. People with cognitive disabilities could be expected to be slower in their bottom-up processing ability and, hence, they were expected to display longer fixation durations. This was not found. With respect to top-down processes, children without cognitive disabilities were expected to be quicker in identifying objects defined as AOIs. This was not confirmed either. However, the first fixation durations were on average longer than expected (413 ms, SD 274 ms, Median 448 ms) [26, 27]. It may be that the children were very interested in the video or had a hard time understanding what the interesting and relevant information in it was. However, given the fixation data the video scenarios were apparently similarly approached by both groups. This finding suggests that the SAFEWAY2SCHOOL system does, in fact, affect the visual search strategies in a similar fashion regardless of cognitive disabilities, which in turn implies that the system could be used by the target group of the present study.
4.4 Trust
The children in both groups trusted the system. They rated it to be safe, secure and reliable. However, to make a valid estimation of the trustworthiness requires real life testing of the system for the target group of the current study. Since the system is already up and running in four European test sites, this is the next logical step in the pursuit to make it accessible and usable for children with cognitive disabilities, as well.
4.5 Accept and act
The travel chain approach [15] is based on the fact that safety and security for children in school transportation is no better than its weakest link. This line of reasoning includes the end users accepting the system and that they actually like to use it. From that perspective it was interesting to notice that overall the participants, regardless of group belonging, were satisfied with the SAFEWAY2SCHOOL system. Children with cognitive disabilities rated lower regarding safety and security, in addition to comfort and how much the system would assist their school transportation. Safety and security are rather abstract concepts when it comes to road safety. Most people are never involved in any crash [28], and the likelihood of children with disabilities to be involved is equally low [6, 7], so safety is hard to measure given the experimental set up of the present study. Security, however abstract it may seem, is probably easier to anticipate for the children, since their parents seem to be able to pick up their child’s feelings of insecurity in the transport situation [29]. Comfort and assistance were also rated lower by CWD, but not low (above 4 out of 5 in both instances). Again, getting the system explained and watching the videos may not be the best way to estimate comfort, but the degree of assistance the system potentially offers may very well be possible to appreciate. They were also asked whether the system seemed to be effective overall, where CWD rated lower but not low. How to estimate the effectiveness of the system may be an issue open for debate and the responses to this ambiguous statement should be taken with this in mind.
4.6 Usage
Looking at possible usage, it was no surprise to find the CWD to a larger extent wanted to learn more before they could use the system. As a matter of fact, it displays an insight into their own cognitive problems, which implies that the training package that comes with the SAFEEAY2SCHOOL system needs to have extra modules for additional training of the target group of the present study. Both groups realised that they will be introduced to the system, but while the Con group were extremely positive, the CWD were a little more cautious.
In order to be a valued member of society that engages in culturally significant occupations such as going to work, playing sports and socialising, transportation is a necessary component of each of these tasks [15, 30–32]. Transport in itself can also be a valued occupation for many [15]. For those with a cognitive or developmental disability who are unable to engage in transportation independently, it can act as a significant barrier to occupational balance and community participation [33]. Public transport is a feasible means of transportation for those with cognitive disabilities as driving is not often an option [33]. Due to a decreased ability to drive and transport oneself, this group often faces social exclusion and are confined to the home which is evidenced by a decreased level of community participation in those with intellectual disabilities when compared to those without [34].
4.7 Limitations
In all, the present study suggests that the next step is to include children with cognitive disabilities into a full scale trial. However, there were several limitations with the present study that should be considered. The limited number of CWD made the entire study prone to type II errors. To give an indication of how prone, non-significant p-values are provided throughout the Section 3. Contrary to this statement, and in line with other applied research, it does make sense not to power studies in order to identify effect sizes under approximately 0.8 (Cohen’s d) or 0.5 (Rosenthal’s r) [18, 19, 35]. In this study the Cohen’s d was actually larger than that, suggesting that the conclusion that CWD could utilise the SAFEWAY2SCHOOL system as equally well as other children could be wrong. However, the p-values do not suggest so. Furthermore, the eye movement analyses did not suffer too low power, since the number of data points (1,604 fixations across all participants) was massive.
Regarding the type I error, in some of the analyses the α-levels were Bonferroni corrected, since the items supposedly measured the same construct. However, the questionnaire has not been tested with Rasch analyses, so the construct assumption has not been properly explored. In addition, Bonferroni corrections are not free of criticism [36]. In the present study only two non-significant findings would become significant if the Bonferroni corrections were abandoned. The major findings would, however, not be altered.
The lack of external validity when using video instead of real world trials is also a limitation. The video stimuli presentation method was chosen to guarantee the safety of the participants. At the same time it provided a high degree of control that excluded possible confounding external factors. It also allowed for straight forward eye movement analyses. What remains unknown is whether or not the video was realistic enough for the children to appreciate it as if they were users of the SAFEWAY2SCHOOL system. However, regardless accuracy any video will only be a representation of the real world. As such, it may have restricted the children to take into account information they would normally use. Hence, future real world studies are therefore needed.