The Route Choice Model Of Urban Road Network Emergency Evacuation Under Ice And Snow

The urban road is a mesh structure infrastructure which exposed under natural conditions, all sorts of climate conditions can have a serious effect on highway network and urban road network. The influence of ice and snow have on the urban traffic operation are commonly large, lightly it will influence road traffic to normal operation and heavily is directly destroy network structure or cause a large area paralyzed.With the acceleration of urbanization, the quickly increase of urban scale and urban population make urban road structure more and more complex, add with frequent emergence events happen, in certain events under emergency, need evacuate a large number of personnel into shelters or security area, by the features of events, we need to take certain evacuation strategy and ways to disperse the crowd quickly and security. Paper study road network traffic characteristic under snow, through on-the-spot investigation get the traffic flow characteristic parameters of different snow conditions, collect and analysis network characteristic data under snow, and on this basis to discuss emergency evacuation traffic characteristic of urban road network under snow conditions.Based on the arrangement and processing of field investigation traffic data, get vehicle operation characteristic parameters under different weather conditions of different highway grade roads and intersection, such as vehicle reach distributions, speed variation characteristics of sections vehicle, road traffic volume change characteristics, intersection vehicles running speed , saturated flow rate and intersection delay, etc; By analysis and fitting of traffic survey data, established the road impedance function under different snow conditions and road level, quantitative the traffic impedance of different snow conditions and road level, established an intersection delay model based on different survey data under different snow conditions, and using this two kinds of impedance format into route impedance model.Paper discussion something related with route choice of emergency evacuation, remove this road or path which not meet basic requirements from the candidate sections or path by a preliminary route choice of emergency evacuation, combined road impedance function model and intersection delay model under ice and snow conditions, and bring this two kinds of model into route selection process of emergency evacuation, finally set up emergency evacuation route choice model based on different ice and snow conditions of urban road network.Through simulation emergency events, applied the route choice model of emergency evacuation in this paper into real network, research route choice characteristics and emergency evacuation time performance characteristics on different snow and ice conditions.