Investigating the Impacts of Truck Platooning on Transportation Infrastructure in the South-Central Region

Truck platooning is an essential application of connected and autonomous vehicles, where several trucks are connected to each other forming a platoon. It is envisioned that truck platooning can assist in minimizing transportation challenges related to freight movements in the US by improving traffic operation, safety and reducing fuel consumption and emission. One of the most valuable truck corridors in the US is in the South-central region. This study investigates the impacts of truck platooning on US highways in that region using both corridor and network-level simulation analysis. Also, the impact of truck platooning on the pavement was quantified using finite element modeling. 

A microsimulation model was developed in Vissim to model the operational, environmental (fuel savings, and emission), and safety impacts of various truck platooning scenarios at the corridor level. An economic feasibility study was also performed to quantify the impacts of truck platoons in monetary terms. The results of the analysis were compared with a base scenario with human-driven trucks. The microsimulation results suggest that truck platooning improved traffic operation, traffic safety, minimize vehicular emissions and fuel consumptions during off-peak hours. However, it deteriorates the traffic performance in the peak period if the truck platoon contains more than two trucks. Recommendations for the best truck platooning configurations during peak and off-peak hours were also provided based on the economic analysis.

In addition to the microscopic analysis, a large-scale analysis of the impacts of truck platooning on congestion and traffic flow dynamics is conducted. Accordingly, a simulation model of I-35 is developed and the impacts of various market penetration rates of truck platooning as well as the size of the platoon on traffic flow dynamics were explored. The findings show that smaller platoons and higher market penetration rates results in less scatter in flow-density diagram and smoother traffic flow.

Finally, the impact of truck platooning on pavement were also addressed using the elastic and dynamic-viscoelastic finite element method (FEM) models. The mechanical response obtained from the simulations are implemented to predict the effects of platooning due to limited wandering (lateral movement of truck tires). Based on the results, it can be concluded that wandering pattern can have influential effect on the fatigue life and permanent deformation damage. Economic analysis shows that the fixed-path platooning can significantly increase the construction-maintenance cost of the pavement.

卡车编队行驶（Truck platooning）是联网与自动驾驶汽车的核心应用场景之一，指多辆卡车通过互联组成编队行驶。学界普遍认为，卡车编队行驶可通过优化交通运行、提升交通安全、降低燃油消耗与尾气排放，缓解美国货运运输面临的各类难题。美国最具代表性的货运通道之一位于中南部地区。本研究依托通道级与网络级仿真分析，探究了卡车编队行驶对该区域美国高速公路的影响。此外，本研究还采用有限元建模（finite element modeling）方法量化了卡车编队行驶对路面的影响。

研究人员在Vissim仿真平台中搭建了微观仿真模型，用于在通道层面模拟不同卡车编队行驶场景下的运行、环境（燃油节约与尾气排放）及安全影响。同时开展了经济可行性研究，以货币化形式量化卡车编队的影响。研究将本次分析结果与人类驾驶卡车的基准场景进行对比，微观仿真结果显示：非高峰时段，卡车编队行驶可优化交通运行、提升交通安全，并减少车辆尾气排放与燃油消耗；但当编队卡车数量超过2辆时，高峰时段的交通运行性能会出现恶化。基于经济分析结果，本研究还给出了高峰与非高峰时段的最优卡车编队配置建议。

除微观分析外，本研究还开展了大规模分析，探究卡车编队行驶对拥堵与交通流动力学的影响。据此搭建了I-35公路的仿真模型，探究了不同卡车编队行驶市场渗透率以及编队规模对交通流动力学的影响。研究结果显示，更小的编队规模与更高的市场渗透率可降低流量-密度图中的离散程度，使交通流更为平稳。

最后，本研究采用弹性与动态粘弹性有限元法（finite element method, FEM）模型，分析了卡车编队行驶对路面的影响。研究利用仿真得到的力学响应，预测了因轮胎有限横向偏移（卡车轮胎的侧向移动）带来的编队行驶影响。基于研究结果可得出结论：轮胎横向偏移模式对路面疲劳寿命与永久变形损伤具有显著影响。经济分析表明，固定路径编队行驶会显著提升路面的建设与养护成本。