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.