一类减少交通阻塞的模型(英文)

The models of decreasing traffic jam

分析了 1 999年美国南卡罗米纳州弗洛依得飓风来临之前 ,人群撤离引起的交通阻塞问题 ,给出了平衡态下的交通流流量、密度、速度之间的函数关系 ,并且研究了改善交通流的策略 ,建立模型并得出了结论 .首先根据流量守衡理论 ,建立了一网络流量模型处理系统的流量问题 .依此 ,获得了 I- 2 6公路车道改向的条件 ,检验了模型的正确性 .此模型还可以推广到更复杂的网络中去 .其次 ,根据流量守衡理论和详尽的推导 ,得到了在交替撤离和改变 I- 2 6周围公路车道方向这两种策略下 ,能够改善交通流的条件 .第三 ,建立了一代数模型来寻求系统流量和建立临时避难所的关系 ,依此找到了在哥伦比亚建立避难所的条件 .用另一代数模型 ,计算出了理想条件下一定大型车比例所决定的撤离时间 .如果该时间比给定的撤离时间还小 ,那么可以不限制车辆类型和数目 ,否则这种限制就是必要的 .最后 ,为了解决交叉路口的拥挤问题 ,建立了一网络流量控制模型 .通过应用一控制函数 ,可以使等待队列的长度尽可能短 .比较各策略的标准是该策略是否改善交通流或减少总撤离时间 .

By the analysis of traffic jam produced by the evacuation before Hurricane Floyd came in 1999 in US,the functional relations among flow rate, velocity and density in balanced state are given. On the basis of the functions and the traffic flow theory,the strategies to improve the traffic flow are studied, models are constructed and some useful conclusions are drawn. First, we construct a net flow model in term of the theory of flow conservation. It is used to process problems of traffic flow of a system. We acquire the condition on which I 26 should be reversed by using the model, and it can be extended to more complex net. Also, we tested the precision of the model. Second, we also use the theory of flow conservation and detailed deduction to acquire the conditions under which the alternative strategy and turning around traffic on the roads besides I 26 can improve the traffic flow. Third, we construct an algebra model in term of theory of conservation to search the functional relation between the number of shelters to be established and flow rate of system. Using the relation , we resolved the problem of establishing shelters in Columbia. We can also use an algebra model to calculate the evacuation time under ideal conditions by controlling the proportion of large scale vehicles. If the time is shorter than the given time, we neednt constrain the types or numbers. Or, the constraint is necessary. At last, to resolve the congestion in intersections, we construct a traffic net controlling model . By using a controlling function, we can make the length of waiting queues as short as possible . We also identify a measure to compare the strategies. It is whether the strategy can improve the traffic flow or decrease the total evacuation time.