Collaborative Research: New Methods for Measuring, Evaluating and Predicting the Safety Impact of Road Infrastructure Systems on Driver Behavior

在这个合作研究项目中，研究人员研究了道路基础设施对驾驶员行为的影响及其对车辆与车辆互动的影响，以及对评估宏观交通网络性能的影响。针对高速公路的几何特征，从交通流理论的角度研究了道路环境对攻击性驾驶行为的影响，分析了道路环境对交通运行的几何影响、道路环境对安全性的几何影响以及道路环境对安全性的影响。为此，研究人员采用了一个统一的交通流框架，其中开发的微观加速度模型和宏观双流体模型是基于风险下的效用最大化（选择）。明确纳入相应的模型中的风险态度和感知参数，同时了解非交通相关的刺激的影响，允许量化的安全影响，不同路段的驾驶员行为。为了校准的交通流模型，解释风险的态度和感知的基础上的道路特征，进行了广泛的数据收集。调查人员集中在三个地理位置不同的地点：华盛顿大都市区和洛杉矶和加利福尼亚州。碰撞数据以及高速公路基础设施的数据收集点的特点是用来验证新的方法与SEM（结构方程法）建模方法。不同的研究结果被用来开发替代的高速公路和高速公路的安全措施，并创建一个原型微观仿真模型捕捉外部非交通相关的特性对不同的模型参数的影响。从更广泛的角度来看，运输问题的特点是找到最有效的方法，以快速和安全的方式将人/货物从起点运送到目的地。在车辆交通中，这些问题转化为避免道路拥堵并减少因交通事件造成的人员和物质损失。这些问题中的主要“参与者”是驾驶员/车辆单元（驾驶员社会人口特征、车辆属性等）和围绕这些单元的驾驶环境（环境条件、交通条件、交通基础设施系统特征等）。在过去的几年里，了解民用基础设施系统对驾驶员行为的影响，特别是相应的安全影响，一直局限于识别“黑点”和定性或统计评估可以采取的安全措施，以避免或应对此类事件的情况。如今，随着车辆行驶里程和相关事故的增加，在这一领域进行大量研究的必要性并不亚于重要，但更广义的模型有助于回答重要的问题：什么是驾驶员的认知特性，道路几何特征的影响？哪些社会人口驱动因素特征和环境/天气特征在这种影响中起主要作用？司机之间的关系是什么？行为和集体交通模式，包括拥堵动态？如何将天气相关和基础设施相关参数纳入交通流模型？为了制定良好的基础设施设计战略和工程解决方案，以实现更安全、更高效的运输系统，需要回答这些基本问题。通过改进交通管理控制系统并考虑冒险行为，所得到的交通流模型在与极端和危险条件相关的风险影响驾驶行为的疏散管理中具有巨大的价值。

In this collaborative research project, the investigators study the impact of roadway infrastructure on driver behavior and its implications on vehicle to vehicle interactions as well as on assessing macroscopic transportation network performance. Focusing on the geometric characteristics of highways and freeways and trying to understand how the road surrounding environment affect the aggressive driving behavior from a traffic flow theory perspective, better insight is given on the geometric effects on traffic operations, geometric effects on safety and effects of operations on safety. For that, the investigators adopt a unified traffic flow framework where the developed microscopic acceleration model and the macroscopic two-fluid model are based on utility maximization (choice) under risk. Explicit incorporation of risk attitudes and perception parameters in the corresponding models while understanding the influence of non-traffic related stimulus allows quantifying the safety implications of different roadway sections on driver behavior. In order to calibrate the traffic flow models that explain risk attitudes and perception based on road features, extensive data collection is undertaken. The investigators focus on three geographically diverse locations: Washington D.C. metropolitan area and the states of LA and CA. Crash data as well as highway infrastructure characteristics of the data collection sites are used for verifying the new approaches with the SEM (Structural Equation Method) modeling approach. The different research findings are used to develop surrogate safety measures on freeways and highways and to create a prototype microscopic simulation model capturing the impact of external non-traffic related characteristics on the different model parameters. From a broader perspective, transportation problems are characterized by finding the most efficient methods to move people/goods from an origin to a destination in a fast and safe manner. In vehicular traffic, these problems translate into avoiding road congestion and reducing human and physical losses due to traffic incidents. The major "players" in these problems are the driver/vehicle units (driver socio-demographic characteristics, vehicle properties, etc) and the driving environment (environmental conditions, traffic conditions, transportation infrastructure system characteristics, etc) surrounding such units. In the past years, understanding the impact of civil infrastructure systems on driver behavior, in particular the corresponding safety implications, have been limited to identifying "black-spots" and assessing qualitatively or statistically the safety measures that can be taken to avoid or respond to such incident scenarios. Nowadays, with the rising number of vehicles-miles travelled and the associated incidents, the need for substantial research in this area is no less important but with more generalized models helping answering important questions: what are the driver cognitive properties that are influenced by the road geometric features? Which socio-demographic driver characteristics and environmental/weather features play the major roles in such influence? What are the relationships between drivers? behavior and collective traffic patterns including congestion dynamics? How can weather-related and infrastructure-related parameters be incorporated in traffic flow models? These fundamental questions need to be answered in order to develop good infrastructure design strategies and engineering solutions for safer and efficient transportation systems. By improving traffic management control systems and considering risk-taking behavior, the resulting traffic flow models have tremendous value in evacuation management where risk associated to extreme and hazardous conditions affect driving behavior.