高速公路与城市道路衔接立交在高交通需求、土地资源紧约束条件下，普遍存在节点效能挖潜不足、占地规模过大等问题，亟待优化升级。鉴于此，本文聚焦新型菱形立交（分叉式菱形立交），针对其传统信号设计方法单一指标导向、分步式优化的局限性，提出时空资源一体化的信号优化设计方法，探究该方法的运行效能与适用特性。首先，基于车辆延误最小化以及绿波带宽最大化双重效能指标，构建新型菱形立交的时空一体优化模型；然后，以武汉—黄石高速公路规划改造的关键节点——蒲团互通为例，对比分析时空一体优化模型和传统分步优化模型的效能表现，评估模型的实际应用效果及其在我国的适用性；最后，利用VISSIM微观仿真，进一步对比分析新型菱形立交与两类典型立交（传统菱形立交、全互通式苜蓿叶立交）的运行效果，为关键节点立交选型提供参考。结果表明：与传统菱形立交相比，尽管新型菱形立交占地面积约增加10%，但车辆延误可有效降低约35%，显著提升整体运行效能；在我国高速公路与城市道路衔接节点的改造中，新型菱形立交在转向流量中等、用地受限的场景下展现出显著的综合效益。

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.