New Zealand now had one of the lowest rates of active travel to school in the world – and it also had one of the highest rates of childhood obesity, costing the country nearly $850 million every year.
In the study, the researchers combined data about the students' travel modes with factors about their environments – including how built-up their neighbourhoods were, how many intersections were in the area and what their distance to school was – using geographic information systems, or GIS.
"Meta-analysis is regarded as problematic to perform in the area of the built environment due to measurement inconsistency between individual studies," Ikeda said.
"However, our review was accomplished by collaborating with several researchers across the country."
Compared with children living within 1.3 km of school, the odds of active transport were reduced by a third among those residing between 1.3km and 2.3 km from school.
Beyond 2.3km, the odds fell to near zero.
Children and youth living in neighbourhoods with the highest density of intersections were almost three times more likely to walk or cycle than those living in neighbourhoods with the lowest – a finding at odds with studies out of Australia, Canada and the US.
The authors also noted the "somewhat counterintuitive" finding which linked a higher number of houses with a lower number of kids walking or biking – something they said warranted further research.
Ikeda said the findings could help toward new policies and programmes, along with improvements to walking and cycling infrastructure.
"For example, planning decisions for school locations and school zoning or catchment policies should consider the impact of distance to school," she said.
"Creating walking and cycle paths, trails and greenways improves street connectivity in school neighbourhoods."
The project was part of a larger investigation to identify "the secret recipe for active school travel", funded by the Ministry for Business Innovation and Employment (MBIE).
Research leader Associate Professor Melody Smith said the project was a "fundamental first step" in generating a more detailed understanding of the complexities that came with encouraging more active travel to school.