A Sustainable Strategy to Upgrade Safety at Traffic System


Traffic safety studies based on crashes data are used to enhance safety by specifying appropriate countermeasures. Rather to wait for crash events, that involve losses in human and properties, this paper demonstrates a sustainable strategy to evaluate and upgrade safety at traffic system as well. The paper demonstrates analysis of traffic conflict "near-crash" data at specified sites in the traffic system. A case study of traffic conflict is performed at selected sites of three legs signalized intersections in Baghdad City. Regression analysis is used to develop model relating observed hourly traffic conflict and average stopped delay. Based on HCM output, a countermeasure is evaluated due to before and after study of average stopped delay and accordingly the involved conflicts based on the developed statistical model.A developed statistical model indicates that 92.5 % of variation in hourly traffic conflict can be described significantly by average stopped delay. In consequence, more than 35 % of potential conflicts can be reduced due to countermeasures and the highest reduction (62.6 %) is due to increase of lane width. This strategy maximizes the usefulness of conflict study as a sustainable aid to predict the effectiveness of any proposed countermeasure, thereby upgrades safety at any traffic system.