Study on Quantitative Analysis of Traffic Conflicts in Traffic Impact

Traffic impact studies (TIS) have been required by transportation agencies to evaluate the potential transportation impacts of the proposed development on the surrounding neighborhood since 2001 in Beijing. The analysis on the negative aspect brought by proposed projects in terms of improper location and excessive number of driveways or inappropriate opening of median becomes the focus of TIS. Traffic conflict is one of the main traffic safety problems that researchers are trying to understand. However, the analysis of the traffic conflicts generated by proposed development has been so far limited to qualitative interpretation and conflict diagrams in traffic impact reports, which makes it difficult for traffic professionals to evaluate traffic organization/circulation plans. The objective of this paper is to explore and quantify traffic conflicts. The concept of conflict complexity is, for the first time, introduced in this study as a new evaluation indicator. The model to estimate conflict complexity is then built up by putting vehicle-bicycle conflict, vehicle-pedestrian conflict and vehicle-vehicle conflict into consideration. This indicator can be used to quantitatively determine if traffic organization and circulation proposed in the TIS report is justified. Finally, based on the data from 65 TIS reports from Beijing city the threshold values for criterion are worked out in the study. The result from this study will help transportation agencies make decisions for the proposed projects in a quantitative manner.