为预测停车政策实施后的实际影响,采用系统动力学方法提出基于出行成本的停车政策评估模型.该模型将各出行方式的出行成本作为出行者出行的选择依据,通过Logit模型模拟政策实施后新的出行方式分布,在此基础上结合路阻函数预测未来路网车速并产生新的出行成本,新的出行成本继续进入模型循环直至整个系统达到稳态.结合杭州市交通拥堵指数平台的武林商圈范围内的路网数据对模型的准确度进行验证研究,发现预测的停车收费影响下的路网车速与实际相对误差为1.1%.结果表明:基于系统动力学建立的综合评价模型能较好地反应路网车速随停车收费的变化规律,并且该模型推测若减少核心区停车供给反而会增加拥堵程度.
The parking policy evaluation model based on travel cost using system dynamics was developed in order to predict the actual effect of a parking policy.The model considered the travel cost as the choice criterions for travelers in a trip,and the new travel choice distribution through the Logit model was simulated,which deduced the future car speed based on bureau of public roads(BPR)function and generated the new travel cost.The new travel cost would be sent into the model for a new cycle until the entire model reached a steady state.The accuracy of the model was verified by the data of Wulin central business district in Hangzhou from Hangzhou Traffic Congestion Index System,which pointed that the related error between the predict speed and the real speed is only 1.1%.The results indicate that the regular pattern of the traffic speed to parking charge can be reflected well using the comprehensive evaluation model based on system dynamics,and the model infers that reducing the parking supply in core area will increase its congestion level.