Assessment & Research

Roadside judgments in children with Developmental Co-ordination Disorder.

Purcell et al. (2011) · Research in developmental disabilities 2011
★ The Verdict

Kids with DCD see cars as slower and wait too long, so teach speed judgment, not just stop-and-look.

✓ Read this if BCBAs writing safety plans for school-age kids with DCD or motor delay.
✗ Skip if Clinicians who only treat verbal behavior or adult populations.

01Research in Context

01

What this study did

The team used a desktop virtual road to test kids with Developmental Coordination Disorder.

Each child watched cars approach and picked when to cross.

The study compared their choices to typically developing peers.

02

What they found

Kids with DCD waited more than twice the normal gap before stepping out.

They also misread how fast the cars were coming.

The errors point to real pedestrian danger.

03

How this fits with other research

Bleyenheuft et al. (2013) and Mengue-Topio et al. (2011) also used virtual rooms to show spatial trouble. Their groups had Down syndrome or intellectual disability and could not find shortcuts, while Catherine’s DCD group could plan a route yet mistimed road entry.

Wilmut et al. (2013) add that DCD reaches stay rough even when the task changes. Together the papers say the problem is not weak muscles but poor forward timing of moving objects.

Provost et al. (2007) and Farley et al. (2022) remind us that motor delay is common across autism and broader developmental delay, so roadside screening should span diagnoses.

04

Why it matters

If you serve a child with DCD, do not assume common-sense traffic rules are enough. Add roadside drills that teach looming speed, not just stop-and-look routines. A simple start is to pause at the curb, name the fastest car, and count the seconds until it passes—then cross.

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→ Action — try this Monday

Before community walks, have the child judge which toy car on a track will reach you first and practice crossing only after they call the speed right three times in a row.

02At a glance

Intervention
not applicable
Design
case control
Sample size
30
Population
developmental delay
Finding
negative

03Original abstract

As pedestrians, the perceptual ability to accurately judge the relative rate of approaching vehicles and select a suitable crossing gap requires sensitivity to looming. It also requires that crossing judgments are synchronized with motoric capabilities. Previous research has suggested that children with Developmental Co-ordination Disorder (DCD) may have deficits in visual processing, specifically in detecting visual motion. It is possible, therefore that this population are at greater risk at the roadside. In a series of motion prediction tasks, several component roadside skills were assessed in 15 children with DCD, or at risk of DCD, aged between 6 and 11 years along with 15 typically developing age and gender matched controls. First, threshold errors for relative approach rate judgments (looming) were measured when vehicle size (car or truck) varied. Second, thresholds for crossing gap selection were measured for vehicle approach speeds of 32, 48, 64 and 80 km/h (20-50 mph). These were related to the walking speeds of children of different ages and profiles. We found that children with DCD showed a deficit in making relative approach rate judgments, using looming, which suggests they may not discern that a vehicle is travelling faster than the urban speed limit. Children with DCD also left considerably longer temporal crossing gaps than controls perhaps reflecting a lack of confidence in their ability, these preferred gaps were over twice the average inter-car gaps that occurred on roads around their school. Our findings raise a number of issues concerning children with DCD and their competence and potential limitations as pedestrians.

Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2010.12.022