为改善高速公路桥梁路段雾天环境的交通安全，文中考虑可变限速标志设置对驾驶行为的影响，从服从效应角度提出其量化评估方法，以期获得最优作用效能。文中以鄂东长江大桥为原型，选取该桥梁近年最低能见度（100 m）和自由流服务水平作为测试环境，设计3种限速策略，分别为对照组S_Ⅰ（无限速策略）、实验组S_Ⅱ（90~70 km/h限速策略）、实验组S_Ⅲ（90~70~50 km/h逐级限速策略）；依托驾驶模拟器，实现不同限速条件的雾天桥梁场景微观驾驶行为数据的细粒度感知，采用重复测量方差分析方法从驾驶人响应的快速性、稳定性及准确性剖析可变限速标志的作用机理及驾驶人特征表现，并通过模糊综合评价方法评估不同限速策略的有效性。研究结果表明：雾天桥梁可变限速标志能够使驾驶人更早地采取减速措施，车辆在雾区行驶过程的稳定性更好；在雾天能见度100 m情况下，90~70~50 km/h逐级限速策略的稳态频数更大，空间稳定性更好，且速度超调量和跟随比更小，响应准确性更高。模糊综合评估结果显示，90~70~50 km/h逐级限速策略作为最优方案，能够有效地提升雾区驾驶行为的调节适应能力，降低驾驶风险，提高车辆运行的稳定性。本研究成果为雾天桥梁可变限速标志的优化设置提供了解决方案，可为雾天桥梁的主动安全防控提供有效支撑。

To improve the traffic safety of highway bridge sections in foggy environments, this paper considered the influence of variable speed limit signs on driving behavior. To obtain the best effect, it put forward a quantitative evaluation method from the perspective of the obedience effect. Taking E’dong Yangtze River Bridge as the prototype, this paper selected the lowest visibility （100 m） and free flow service level of the bridge in recent years as the test environment. Three speed limit strategies were designed, namely, the control group S_Ⅰ (no speed limit strategy）, the experimental group S_Ⅱ (90~70 km/h speed limit strategy), and the experimental group S_Ⅲ (90~70~50 km/h step-by-step speed limit strategy）. Relying on the driving simulator, the micro-driving behavior data of foggy bridge scenes with different speed limit conditions were realized. The action mechanism of variable speed limit signs and driver characteristics were analyzed from the rapidity, stability, and accuracy of driver response by repeated measure analysis of variance, and the effectiveness of different speed limit strategies was evaluated using the fuzzy comprehensive evaluation method. The results show that the variable speed limit sign can make the driver take deceleration measures earlier, and the vehicle’s stability in the fog area is better. When the visibility is 100 m in fog, the steady-state frequency of 90~70~50 km/h step-by-step speed limiting strategy is more significant, the spatial stability is better, the speed overshoot and the following ratio are more minor, and the response accuracy is higher. The results of the fuzzy comprehensive evaluation show that the 90~70~50 km/h step-by-step speed limit strategy, as the optimal scheme, can effectively improve the adaptability of driving behavior in fog areas, reduce driving risk, and improve the stability of vehicle operation. The research results provide a solution for setting variable speed limit signs for bridges on foggy days and can provide adequate support for the active safety prevention and control of bridges on foggy days.