Research On Practical Velocity-Volume Model Of Urban Streets

Urban roadway network is among the most interested research topics of urban transportation system, especially as the traffic flow characteristics such as relationships between velocity and volume. It is the hotspot of international research and is very important to the following research topics: forecasting the average velocity and average of roadway section, roadway network traffic assignment, evaluation of network quality and economical evaluation of roadway networks. It is also the foundation of partition the level of service (LOS) and roadway capacity study; it has many applications in transportation planning of roadway networks and so on. According to continues development of transportation utilities in our country, it is urgent to establish our new practical roadway traffic flow velocity-volume model; it has its special meanings both in theory and in practices.The project is subject to the National Outstanding Youth Funding project: "Research on Theory System of Urban Transportation Management Planning" (2000-2003). The paper forwards the concept of adapted S-curve model and re-demarcates the parameters, by analyzing the unconformity between classical model and our country's unique conditions. Then, based on basic theory studies together with preparation works, the research focuses on the survey technique and the technique used in processing the large volume of survey data, which are essential to the establish of model. The methods of survey and new statistical interval were adapted, too and large volumes of field data were collected to do the modeling. Based on the field data, the new S-curve velocity-volume model was created and verified, the parameters are reasonable and the conclusion can be applied to the very different road types. Several other factors such as effects of intersection, effects of bus/bus stations etc. are studied in order to adjust the parameters again, the S-curve model is tested again and proved to be more applicable.Finally, the conclusion is made to confirm the new S-curve model's practicability. The further studies should be focused on the enlargement of data sets and the environmental varieties. The paper laid down a good foundation of further research in this aspect.