A Cochrane Systematic Review of research evidence for the effectiveness of visibility aids (fluorescent and retroreflective clothing and equipment) was carried out by Kwan and Mapstone in 2006. The authors found 42 studies which collectively suggested that fluorescent clothing could increase the distance at which drivers could detect and then recognise cyclists in daylight conditions. The same review found evidence that retro-reflective materials worn by cyclists at night had a similar effect on driver perceptions. At that time there were no studies published that had actually demonstrated a reduction in collision crashes for bicyclists wearing fluorescent or retroreflective clothing whilst on public roads.