Study design
Of the 21 studies, 16 were cross-sectional surveys of which eight also conducted spatial analysis using GIS. Three studies were quasi-longitudinal surveys. One study was an observational census of cycle routes and one was a secondary analysis of census information. Only three studies included an intervention (the construction of cycle lanes, the ‘safe
routes to school programme’ and the development of a disused railway into a multi-use trail). Only two studies included a control group. The nature of the studies meant that none could incorporate blinding, and cross-sectional designs precluded assessment of loss to follow-up. These weaknesses meant that overall the studies did not score highly in the quality assessment tool.