Department of Civil, Environmental and Construction Engineering, University of Central Florida, Engineering II - 215 Orlando, FL 32816, USA.
Accid Anal Prev. 2011 Jul;43(4):1581-9. doi: 10.1016/j.aap.2011.03.021. Epub 2011 Apr 13.
While rural freeways generally have lower crash rates, interactions between driver behavior, traffic and geometric characteristics, and adverse weather conditions may increase the crash risk along some freeway sections. This paper examines the safety effects of roadway geometrics on crash occurrence along a freeway section that features mountainous terrain and adverse weather. Starting from preliminary exploration using Poisson models, Bayesian hierarchical models with spatial and random effects were developed to efficiently model the crash frequencies on road segments on the 20-mile freeway section of study. Crash data for 6 years (2000-2005), roadway geometry, traffic characteristics and weather information in addition to the effect of steep slopes and adverse weather of snow and dry seasons, were used in the investigation. Estimation of the model coefficients indicates that roadway geometry is significantly associated with crash risk; segments with steep downgrades were found to drastically increase the crash risk. Moreover, this crash risk could be significantly increased during snow season compared to dry season as a confounding effect between grades and pavement condition. Moreover, sites with higher degree of curvature, wider medians and an increase of the number of lanes appear to be associated with lower crash rate. Finally, a Bayesian ranking technique was implemented to rank the hazard levels of the roadway segments; the results confirmed that segments with steep downgrades are more crash prone along the study section.
虽然农村高速公路的事故率通常较低，但驾驶员行为、交通和几何特征以及不利天气条件之间的相互作用可能会增加某些高速公路路段的事故风险。本文研究了在具有山区地形和不利天气条件的高速公路路段上，道路几何形状对事故发生的安全影响。本文从使用泊松模型进行初步探索开始，开发了具有空间和随机效应的贝叶斯层次模型，以有效地对研究中 20 英里高速公路路段的道路段的碰撞频率进行建模。研究使用了 6 年（2000-2005 年）的碰撞数据、道路几何形状、交通特征和天气信息，以及陡坡和雪季及旱季不利天气的影响。模型系数的估计表明，道路几何形状与碰撞风险显著相关；发现陡峭的下坡路段会大大增加碰撞风险。此外，与旱季相比，雪季的这种碰撞风险可能会显著增加，因为坡度和路面状况之间存在混杂效应。此外，曲率较大、中央分隔带较宽以及车道数量增加的路段似乎与较低的碰撞率相关。最后，实施了贝叶斯排名技术来对道路段的危险水平进行排名；结果证实，在研究路段上，陡峭的下坡路段更容易发生碰撞。
