Analysis of dynamic road risk for pedestrian evacuation

• We develop an optimal mathematical model to simulate pedestrian evacuation.
• Pedestrian counterflow and illegal vehicles parking evidently influence evacuation.
• Optimized city planning and road design can improve evacuation efficiency a lot.
• Real time governmental guidance can bypass evacuees to different roads.
• Evacuation planning based on road risk evidently improves evacuation efficiency.

Knowing the dynamic road risk for pedestrian evacuation and having an efficient evacuation plan play a very important role in the serious disasters such as earthquake, tsunami and hurricane. In this paper, the dynamic road risk for pedestrian evacuation in a densely populated area of Beijing was studied with consideration of different influencing factors. Firstly, the eight influencing factors including road width, node degree, safety betweenness, road resistor coefficient, building threat, pedestrian counterflow, illegal vehicle parking and traffic flow were considered to assess the road risk for pedestrian evacuation. Secondly, based on complex network theory, electric circuit theory and real situation of the roads, the comprehensive assessment function for road risk was developed quantitatively based on the eight influencing factors. Thirdly, we analyzed road risk for pedestrian evacuation considering different situations: current condition, regular condition, and optimal condition; the risk distribution maps were drawn to directly show the risk level. Through assessments, the roads with high risk for pedestrian evacuation were found, and an optimized evacuation plan was obtained and analyzed. This mathematical model can guide the emergency evacuation in real time. The process and the results are essential for improving the efficiency of evacuations which should considerably reduce the possibility of injuries, deaths and other losses in the disaster.