高速公路改扩建后增加两侧立体层可以提高通行能力，但互通立交处常常会出现间距过短、流量过大、分流过多等问题，进而导致现有的交通标志无法满足驾驶人的指路需求。针对此问题，以深圳机荷高速为例，在常规标准方案基础上，设计了4种匝道指引标志提升方案，并使用Unity3D引擎开发出了相对应的立体复合高速公路互通场景，高速公路上的车辆第1次分流时驶出地面层，第2次分流可以驶入立体层，第3次分流接入其他互通高速。28名驾驶人使用外接交互设备在不同的场景中进行模拟驾驶，实验采集到了速度、加速度、车道位置等驾驶行为数据。通过计算不同指引标志设计方案中各影响区段内指标的逐点显著性，呈现出了各指标空间维度上的差异性，进一步分析表明，增加预告层级设置3 km预告标志能够帮助驾驶人及早感知前方匝道状况；设置车道指引标志可以提升车辆在匝道处的纵向和横向稳定性，便于驾驶人采取更好的换道策略；导航语音辅助能够提升驾驶人在立体复合高速公路匝道处的速度控制水平、出口换道意识和心理舒适程度。研究表明，Unity3D保真度高、交互性好、成本低，可以为复杂道路场景中驾驶行为的相关研究提供技术支持。同时，该研究也为高速公路改扩建工程交通指引标志设立提供了理论参考。

By adding bilateral elevated layers, the renovation and expansion of the expressway have improved the traffic capacity, but a subsequent rise in problems, such as insufficient spacing, excessive traffic volume, and multi-diversion, has made the existing traffic signs fail to meet the drivers’ guidance needs. In response to this issue, this study took the Ji-He Expressway in Shenzhen as an example and designed four optimized traffic sign schemes of interchange based on the conventional standard scheme, and developed the corresponding stereoscopic compound expressway scenes by the Unity3D engine. The vehicles on the expressway will drive out of the ground-level road at the first diversion, enter the elevated-level road at the second diversion, and connect to other expressways at the third diversion. 28 drivers simulated driving in different scenes using external interactive devices, and their driving behavior data such as speed, acceleration, lane position, etc., were obtained. By calculating the point-by-point significance of indicators within each affected section in different guidance sign design schemes, differences in spatial dimensions of each indicator were presented, and further analysis shows that 3 km warning signs can help drivers perceive the situation of the ramp ahead as early as possible. Lane guidance signs can improve the longitudinal and lateral stability of vehicles at the ramp, and drivers can take better lane changing strategies. Navigation voices assistance can improve the driver’s speed control proficiency, lane changing awareness of expressway exits, and psychological comfort at the interchange of stereoscopic compound expressway. The research shows that Unity3D has high fidelity, good interactivity, and low cost, and it can provide technical support for relevant research on driving behavior in complex road scenes in the future. At the same time, this study also provides a theoretical reference for the establishment of traffic guidance signs in expressway renovation and expansion projects.