Visual search strategies in a shared zone in pedestrians with and without intellectual disability.
Adults with ID miss most traffic cues in shared streets—give them bold visual or audio signals before they cross.
01Research in Context
What this study did
Earl et al. (2019) filmed adults walking through a shared zone. A shared zone is a street where cars and people mix with no clear crossing lines.
Half the adults had an intellectual disability. Eye-tracking glasses recorded where they looked. The team counted fixations on traffic-relevant objects like cars, bikes, or road signs.
What they found
Adults with ID looked at traffic objects only 68 % as often as the other group. Males with ID spent more time staring at non-traffic items like shop windows or litter.
Missing traffic cues means they may step out without seeing danger.
How this fits with other research
Merrill (2004) saw the same weak visual filtering in a lab. When rules kept changing, adults with ID did not slow down as much as neurotypical adults. The street study extends that lab result to real traffic.
Wang et al. (2022) also used eye-tracking and found large search problems in adults with cerebral visual impairment. Both papers show that clutter hurts visual search, whether the cause is ID or CVI.
Oppewal et al. (2018) found adults with ID walk like people 20 years older—less stable and more variable. Together the three papers paint a full picture: shaky steps plus missed sights equal high pedestrian risk.
Why it matters
If you teach street safety, do not assume clients will notice cars. Add bright cones, flags, or audible beeps to make traffic cues pop. When possible, pick striped crosswalks over shared zones. Practice scanning left-right-left with extra prompts until fixations on traffic reach neurotypical levels.
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02At a glance
03Original abstract
People with intellectual disability (ID) may find shared zones troublesome to negotiate because of the lack of the traditional clearly defined rules and boundaries. With the built environment identified as a barrier to active travel and community access, it is vital to explore how pedestrians with ID navigate shared zones to ensure that this group is not placed in harm's way or discouraged from active travel because of the implications of shared zones. This study investigated the visual strategies of 19 adults with ID and 21 controls who wore head mounted eye trackers in a Shared Zone and at a zebra crossing (as a contrast traffic environment). In total 4750 valid fixations were analysed. Participants with ID fixated on traffic relevant objects at a rate of 68 percent of the control participants. Furthermore, the males with ID were 9(4.4-18.7) times more likely to fixate on non-traffic relevant objects compared with traffic relevant objects, much higher odds than that of females with ID 1.8(0.4-1.7). Zebra crossings appeared to act as a cue, drawing pedestrians' visual attention to the traffic environment, with both groups more likely to look at traffic relevant objects on/at the zebra crossing (66%: 34%). Future implementation of shared zones needs to be carefully considered in relation to the safety of road users with ID and their capacity to identify and assess salient environmental information.
Research in developmental disabilities, 2019 · doi:10.1016/j.ridd.2019.103493