安全与效率协同的高速公路改扩建时机决策

Timing decision of highway reconstruction and expansion in coordination of safety and efficiency

为克服以饱和度确定改扩建时机无法全面体现高速公路运行状态的局限性,提出基于交通安全与效率状态变点的改扩建时机决策方法。以严重交通冲突率为安全指标,以速度损失率和相对通行效率为效率指标,构建改扩建时机评价指标体系;引入变点理论并参考理想点法分析交通安全与效率状态质变点,构建改扩建指标阈值确定模型及改扩建时机决策模型,并以广深高速南头-南坪段进行仿真和实例分析。结果表明:以饱和度作为对比指标进行趋势分析,该方法所选取指标在变点前后变化幅度均在300%以上,而饱和度在变点前后变化幅度仅为18%;该方法确定出的改扩建最佳时机2020年与服务水平法确定的2025年相比,既有高速公路两半幅的严重交通冲突率分别降低了41.11%与43.52%,速度损失率分别降低33.95%与29.26%,南头至南坪段相对通行效率提高9.46%,且避免了南坪至南头段相对通行效率的降低。

In order to overcome the limitation that the timing of reconstruction and expansion cannot fully reflect the operation status of highway by saturation degree,a reconstruction and expansion timing decision method based on traffic safety and efficiency state change points was proposed.The safety indicator was the serious traffic conflict rate,and the efficiency indicator was the speed loss rate and relative traffic efficiency,so as to build an evaluation index system for the timing of expansion.Simulation and example analysis were conducted with the Nantou-Nanping section of Guangshen expressway,and the results showed that:using saturation as the comparison index for trend analysis,the selected indexes in this paper change by more than 300%before and after the change point,while the saturation change by only 18%before and after the change point.By comparing the best re-expansion timing of 2020 determined by the method in this paper and 2025 determined by the service level method,the serious traffic conflict rates of the two halves are reduced by 41.11%and 43.52%,the speed loss rates are reduced by 33.95%and 29.26%,the relative traffic efficiency of the Nantou to Nantou section is increased by 9.46%,and the reduction of relative traffic efficiency in the Nantou to Nantou section is avoided.