The Research Of Emergency Rescue Path Selection Method On The Degraded Road

The impact of rapid development of social economy, the continuous expansion of city and various uncertain factors (such as rain and snow weather, traffic accidents, fog and haze, and large-scale power outages, etc) can cause serious harm to people’s life and property safety incidents. The management have been fully realized the importance of rapid and reliable emergency rescue, and the problem of emergency rescue path selection is the key. In fact, the time-varying traffic, occasional accidents, unexpected traffic congestion and traffic control,etc, will cause the attenuation of global or local network capacity and the varying degrees of downgrading road network capacity, resulting in the random vehicle travel time on the road, all above will leading to the stochastic shortest path between the rescue center and the accident place.As the urgency and uncertainty characteristic of the emergency rescue vehicle routing problem, this determine the method for solving vehicle routing problem under normal conditions are not suitable for emergency response issues, thus the research of emergency rescue path on the degraded road, can make up the shortcomings of emergency rescue path selection theory when the network downgrade, and have some reference to the decision of emergency rescue managers.The thesis mainly studies the emergency rescue path selection problem as the network downgrade. Firstly, putting forward the research ideas and the overall framework through inductive analysis of domestic and foreign downgrade road network, emergency rescue path selection and travel time reliability research status. Nextly, after defining the downgrade road network the downgrade road network travel time and reliability expectations model are established, the characteristics of emergency rescue is analysised and the factors is determined that affect the emergency rescue path selection by comparing with the factors influencing the choice of vehicle routing under normal conditions. Then, considering the random change point, congestion and congestion time traveler psychology decision function, the thesis puts forward to a flexible routing strategy which congestion is pointed as the starting point when the city road network is demoted and capacity decline; the multi-goal weighted programming model of emergency rescue path with the emergency rescue path to the shortest expected travel time and biggest reliability travel time for the target is constructed; the adaptive strategy pheromone evaporation factor and pheromone dynamically adaptive strategies based on the Basic Ant Colony Algorithm is proposed, and the transition probability formula is improved, emergency rescue path selection algorithm model based on the Improved Ant Colony Algorithm is designed. Finally, through the case study of downgrade emergency rescue network routing issues and compare with the minimizing travel time path routing problem, the weighted model shows its feasibility and is more in line with the emergency rescue path selection truth.