The Study Of The Traffic Demand Forecasting Model For The Medium-small Cities

The aim of the urban traffic management planning is to establish the systemic management and development program of the urban traffic, which can solve the traffic problems in the urban planning period, and set down the plan of urban traffic management and the corresponding traffic management facility. Accurate traffic demand forecasting is a precondition to make the reasonable planning program and is the important gist to make certain the layout and capability of the urban traffic road network. The veracious level of the model and the algorithm will directly restrict the reasonable degree and the scientific level of the traffic management planning. The traffic demand forecasting model used frequently is based on the traffic character of the metropolis in our country. If it's used to forecast the medium-small cities traffic demand, there will have lots of shortages. For example, the traditional demand forecasting model is not sensitived to the change of the land-use, needs a lot of traffic base data, is lack of consideration to the mobile and unmobile mixed traffic, and so on. This paper makes systemic analysis to the study status quo of the traffic demand forecasting model firstly, and then makes some corresponding amendment to the "four stages" forecasting model, for the traffic characters of the medium-small cities, such as lacking of traffic base data,big changes in the land-use layout,serious mixed traffic, and so on.There have mutual influences between the development of the urban land-use and the development of the urban traffic. Because of the economy development, the medium-small cities have big changes in the urban land-use. After taking into account the traffic accessibility and the urban land-use, this paper, based on the traditional trip generation forecasting model, introduces the region potential energy to reflect the urban land-use of the medium-small cities.The discrete model of the trip mode split forecasting needs lots of traffic base data. And the trip mode structure of the medium-small cities is affected largely by the policy,the development of the traffic facility and so on. So, in the trip mode split forecasting of the medium-small cities, the paper applies the combination between the macro-forecasting and micro-forecasting, the macro-forecasting supervises the micro-forecasting.To the bi-Ievel model for the estimation of the Origin-Destination matrix from the traffic flows which used currently in present, the paper puts forward the single-level model based on the uncertain consideration for the traffic flow. This model simplifies the traditional model but guarantee the accuracy of the forecasting results.Compared with the traffic congestion in the metropolis, the phenomenon of the mobile and unmobile mixed traffic in the medium-small cities is more obviously. The influence of the mobile which is from unmobile is in the person of the road capacity. In the traffic assignment forecasting of the medium-small cities, for the demarcating of the road attribute, the paper divides the influence into four classes to analyze the capacity of the mobile roadway, which are the little interference,middle interference,large interference and the serious interference.The model and the arithmetic in this paper is based on the program of the traffic management planning in the HongTa district of the YUXI. Finally, the computerization of the model and arithmetic comes true by the transportation software TransCAD. The model and the arithmetic improves the precision and briefness of the traffic demand forecasting in the medium-small cities, which has a good effect in the actual project. The study result in this paper can be a reasonable and effective way in the traffic demand forecasting of the medium-small cities, which has important practical value.