The effect of traffic calming on pedestrian injuries and motor vehicle collisions in two areas of the eThekwini Municipality: a before-and-after study.

BACKGROUND Motor vehicle collisions and pedestrian injuries in areas where schools are located are public health problems in Durban. OBJECTIVE To evaluate the effect of traffic calming humps on the number and severity of incidences of collisions and injuries in the Chatsworth and KwaMashu residential areas of the eThekwini Municipality. METHODS The evaluation used an observational interrupted time-series study design, with data obtained from the eThekwini Traffic Authority for roads constituting the routes to 34 schools for 2 years prior to and following the implementation of road humps (excluding the intervening year of implementation). A non-probability convenience sample of 19 schools with 39 roads in Chatsworth and 15 schools with 24 roads in KwaMashu was selected. RESULTS The traffic calming humps improved safety in both areas with respect to the severity of collisions. Serious pedestrian-vehicle collisions (PVCs) dropped by 23% and 22%, while fatal collisions decreased by 68% and 50% in Chatsworth and KwaMashu, respectively. The median annual PVC rate/km of road/year decreased from 1.41 to 0.96 (p=0.007) and from 2.35 to 1.40 (p<0.001) in Chatsworth and KwaMashu, respectively. There was a 1.6% reduction in the median number of fatal or serious PVCs after implementation in Chatsworth (p=0.03) while in KwaMashu, although the number of collisions decreased, the median number increased by 9% (p=0.07). CONCLUSIONS Traffic calming has been shown to be effective in reducing the number of PVCs but needs to be supported by additional measures to further improve the safety of pedestrians.