新型菱形立交时空一体优化设计方法OA

The interchanges connecting expressways and urban roads generally suffer from inadequate tapping of node operational efficiency and excessive land occupation under the conditions of high traffic demand and tight land resource constraints,which necessitates urgent optimization and upgrading.Aiming at the limitations of single-index orientation and stepwise optimization in its conventional signal design methods,the research focuses on the new diamond interchange(also known as the Diverging Diamond Interchange,DDI),proposes a signal optimization design method for integrated allocation of time and space resources,and explores its operational efficiency and applicability characteristics.Firstly,based on the dual performance indicators of minimizing vehicle delays and maximizing green wave bandwidth,a time-space integrated optimization model for the new diamond interchange was constructed.Then,taking the key node of the Wuhan-Huangshi Expressway planning and reconstruction—the Putuan Interchange—as an example,a case study was conducted to compare the performance of the spatio-temporal integrated optimization model with that of the traditional stepwise optimization model,evaluating the practical application effect of the model and its suitability in China.Finally,VISSIM-based microscopic simulations were applied to compare the operational performance of the new diamond interchange with two typical types(conventional diamond interchange and full cloverleaf interchange)to provide decision-making support for interchange selection at critical nodes.The result indicated that compared with the traditional diamond interchange,the new design requires slightly more land(approximately 10%)but reduces vehicle delay by about 35%,significantly improving overall operating efficiency.In the reconstruction of interchanges connecting expressways and urban roads in China,the new diamond interchange has demonstrated significant overall benefits in scenarios with moderate turning traffic and limited land availability.