Effective Safety Factors on Horizontal Curves of Two-lane Highways

Aram, Ali

doi:10.3923/jas.2010.2814.2822

Cited by 47 publications

(18 citation statements)

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“…This result indicated that the first horizontal curve after a long tangent experienced as much as 1.5 times the number of accidents that can be occurred along tangent section. This result is within the range of findings of previous studies because some few studies stated that horizontal curves experienced crash rate of up to four times the rates on tangent sections [5] [6]. And followed by from three curves to four curves per segment section of the road and accounted around 43%.…”

Section: Influence Of Number Of Hc Per 15 Km Segment Lengthsupporting

confidence: 86%

“…Other studies indicated that radius of path, curve length of path, number of curves in the path, number of horizontal curves that are very close to each other and interference of horizontal and vertical curves have significant roles in the occurrence of accidents [6] [7] [8]. Other studiesss also revealed that the crash frequency increased as the horizontal curve radius decreased, the length of the vertical curve increased, and the sharpness of the vertical curve increased [9].…”

Section: Road Geometric Parametersmentioning

confidence: 99%

“…Radius of horizontal curves: Research results showed that the number of road accidents tends to decrease when the radii of horizontal curves increase [6] [7] [8] [10] [11] [12]. The effect of horizontal curves of low radii lead to road safety problems, hence small radii have been characterized by a higher accident frequency as well as accident severity [8] and the related risk rates increased significantly for radii less than 200 m [10].…”

Section: Horizontal Curve Elementsmentioning

confidence: 99%

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Quantifying the Influence of Road Geometric Parameters on Road Safety (Case Study: Hawassa-Shashemene-Bulbula Rural Two-Lane Highway, Ethiopia)

Abebe¹

2019

JTTs

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Road safety depends on humans, vehicles, and highway conditions. These factors influence road safety separately or in combination. Despite these facts, the police report indicated that only a single cause of accident has been reported for a given accident in Ethiopia and the number of accidents that had been caused by road defect accounted around 1% of total accidents per year, which underestimates its contribution to road accidents. Beside these facts, only a few studies were carried out in Ethiopia on this issue. Even though dangerous road segments were identified and ranked along the same study area of this paper in our previous publication, Hawassa-Shashemene-Bulbula two-lane rural highway, the influences of road geometric parameters on road safety were not correlated along this study area. Therefore, it is imperative to clarify the relationship between the expected number of traffic accidents and the geometric conditions of the road under study to reduce accidents and provide safe driving environment. The main objective of this study was to quantify the influence of road geometric parameters on road safety. Using historical accident data, traffic data, and road data, the expected numbers of accidents were estimated by using the empirical Bayes (EB) method. Then, the expected numbers of accidents have been correlated with one or more road geometric parameters at a time. Accordingly, the identified dangerous road segments in the previous publication

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Section: Influence Of Number Of Hc Per 15 Km Segment Lengthsupporting

confidence: 86%

Section: Road Geometric Parametersmentioning

confidence: 99%

Section: Horizontal Curve Elementsmentioning

confidence: 99%

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Quantifying the Influence of Road Geometric Parameters on Road Safety (Case Study: Hawassa-Shashemene-Bulbula Rural Two-Lane Highway, Ethiopia)

Abebe¹

2019

JTTs

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“…The studies related to road characteristics include the curve radius/ curvature (Coutton-Jean et al, 2009;Bella et al, 2014;Boer, 1996), edge lines (Coutton-Jean et al, 2009), lane width (Robertshaw and Wilkie, 2008;Coutton-Jean et al, 2009), curve length (Zuriaga et al, 2010;Hu and Donnell, 2010) and pavement condition (Buddhavarapu et al, 2013;Zador et al, 1987). The research related to environmental conditions in curve segments includes weather conditions (Jung et al, 2014;Yan et al, 2014), nighttime (Bella et al, 2014;Hu and Donnell, 2010), roadside clearance (Aram, 2010;Bella, 2013), sight distance (Kondo and Ajimine, 1968), traffic volume (Aram, 2010;AASHTO, 2010) and markings and speed signs (Rutley, 1972;Comte and Jamson, 2000). The vehicle-related factors can significantly influence the relevant driving behaviors and running out of curve crashes, such as vehicle type (Liu and Subramanian, 2009;Fitzsimmons et al, 2013) and vehicle occupancy (Liu and Ye, 2011).…”

Section: Factors Associated With Curve Safetymentioning

confidence: 98%

Effects of fog, driver experience and gender on driving behavior on S-curved road segments

Yan

Wong

2015

Accident Analysis & Prevention

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Driving on curved roads has been recognized as a significant safety issue for many years. However, driver behavior and the interactions among variables that affect driver performance on curves is complicated and not well understood. Previous studies have investigated various factors that influence driver performance on right- or left-turn curves, but have paid little attention to the effects of foggy weather, driver experience and gender on driver performance on complex curves. A driving simulator experiment was conducted in this study to evaluate the relationships between driving behavior on a continuous S-curve and foggy weather, driver experience and gender. The process of negotiating a curve was divided into three stages consisting of a straight segment, the transition from the straight segment to the S-curve and the S-curve. The experimental results indicated that drivers tended to drive more cautiously in heavy fog, but the driving risk was still increased, especially in the transition stage from the straight segment to the S-curve. The non-professional (NP) drivers were less sensitive to the impending change in the road geometry, and less skilled in both longitudinal and lateral vehicle control than the professional drivers. The NP female drivers in particular were found to be the most vulnerable group in S-curve driving.

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“…Horizontal curves are, in effect, transitions between two tangents. These deflection changes are necessary in virtually all highway alignments to avoid impacts on a variety of field conditions (e.g., right-of-way, natural features and manmade features) (AASHTO, 1994;Aram, 2010).…”

Section: Introductionmentioning

confidence: 99%

Developing a Computer Program for the Methods of Radius-Estimating Techniques for Horizontal Curves

Ibraheem¹

2011

American Journal of Engineering and Applied Sciences

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Problem statement:This study discusses the development of computer software of two phases. First phase contains the calculations of all curve elements of the four types of the horizontal curve and second phase contains the modeling of the ten methods of estimating the radius of the horizontal curve. Approach: The program is named as HCRET, which stands for Horizontal Curves and Radius Estimating Techniques. The program is written in Visual Basic-Version 6 language. The developed program deals with the calculation of all elements of the horizontal curve of the four types of the horizontal curves, which consists of simple, compound, reverse and transition. Results: The program also used for modeling of the ten methods of radius-estimating of horizontal curve, which consist of Ball Bank Indicator, Chord Length, Compass, Lateral Acceleration, Plan Sheet, Advisory Speed Plate, Modified Yaw Rate, Field Survey, and Global Positioning System for the calculation of estimated-radius. The program output is comprehensive and easy to understand, while the program input is used friendly and provided with many graphical objects to facilitate ease of use. A case study of three examples presented to evaluate the modeled software of three horizontal curves. Two curves were located in university of Baghdad and a third curve was designed and includes also the experimental work of radius-estimating methods of horizontal curves as follow field survey, plan sheet, compass, Global Positioning System (GPS). Conclusion/Recommendations: The results that obtained of the three curves by using the radius-estimating methods include the true and estimated radius of each method. The field survey and the plan sheet method provided the most accurate result 0.8002 and 0.8660 respectively. The plan sheet method and GPS method is preferred, because plan sheets are easily accessible to these users and GPS is the accurate field method. While the compass method is not the accurate, it is easy to use, and has a low cost.

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Effective Safety Factors on Horizontal Curves of Two-lane Highways

Cited by 47 publications

References 1 publication

Quantifying the Influence of Road Geometric Parameters on Road Safety (Case Study: Hawassa-Shashemene-Bulbula Rural Two-Lane Highway, Ethiopia)

Quantifying the Influence of Road Geometric Parameters on Road Safety (Case Study: Hawassa-Shashemene-Bulbula Rural Two-Lane Highway, Ethiopia)

Effects of fog, driver experience and gender on driving behavior on S-curved road segments

Developing a Computer Program for the Methods of Radius-Estimating Techniques for Horizontal Curves

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