Evaluation of the benefits of traffic calming on vehicle speed reduction

Vehicle speed is one of the main risk factors for road traffic safety. To increase the level of road safety, especially in urban areas, measures must be implemented to reduce vehicle speed. The installation of calming measures on a road network is systematically planned way to reduce driving speeds. This paper studies the effectiveness in terms of speed reduction of three types of traffic calming measures: 1) speed table, 2) chicane, and 3) road narrowing. The speed analyses regard a series of traffic calming measures located in urban contexts of Catania Province (Italy). For each of these traffic calming measures, experimental investigations were carried out relating to the measurement of speed. The study has shown that the speed tables represent the measure of traffic calming that guarantees the greatest conditioning on speed (it is also possible to halve the average speed). Even the chicanes have a significant impact on reducing speed, as well as the speed tables (average speed is reduced by up to 50%), while road narrowing allows maximum reductions in average speed of around 35%. Furthermore, all three traffic calming measures have resulted in a reduction of accidents always greater than 30%. In the case of speed tables, the reduction in accidents exceeds even 40%. The consequences of road accidents are also mitigated thanks to the traffic calming interventions considered. The reduction of injured people is between 32% (road narrowing) and 50% (chicane). The speed tables involve a reduction of almost 40% of injured people while fatal accidents are completely eliminated. Finally, it has been observed that the reduction in pedestrian injuries is between 33% (road narrowing) and 50% (speed tables). In the case of the chicane the reduction of injured pedestrians is 40%. The pedestrian fatal accidents in the road section in which the speed tables were subsequently installed have been reduced to zero