Assessing the Risk in the Design of Passing Sight Distances

Khoury, John El; Hobeika, Antoine G.

doi:10.1061/(asce)0733-947x(2007)133:6(370)

Cited by 37 publications

(29 citation statements)

References 3 publications

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“…The application of this tool to the evaluation of passing sight distance may account for existing variability and for the risk of deviating from design and marking standards. Although previous work (24)(25)(26) have already performed reliability analyses for this application, input parameters were not characterized from real data.…”

Section: Discussionmentioning

confidence: 99%

Sight Distance Standards Based on Observational Data Risk Evaluation of Passing

Llorca

Moreno

Sayed

et al. 2014

Transportation Research Record

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This paper presents an application of reliability analysis for evaluating the risk associated with passing sight distance standards in terms of expected probability of noncompliance.The calculation of passing sight distance (PSD) is required to determine where drivers can safely execute passing maneuvers. Traditional PSD standards are based on deterministic, theoretical models, which are calibrated using conservative percentiles values for uncertain design inputs to account for uncertainty. They do not provide information about the risk of deviating from them. Reliability analysis is a technique based on limit state design that accounts for the propagation of variability from input random parameters to the design outputs.A total of 1,098 passing maneuvers were observed on several two-lane highways in Spain, using two different data collection methodologies: external observations and instrumented vehicle. The most significant factors affecting PSD were: impeding vehicle speed, passing vehicle acceleration, and headways between impeding and passing vehicles. A uniform acceleration model described passing vehicle trajectory. The characterized input parameters and the passing model were used to perform a reliability analysis. The results showed the probability of noncompliance in different scenarios, defined as the proportion of cases where the required PSD would exceed the available sight distance.American and Spanish PSD standards were evaluated. Geometric design standards presented a probability of noncompliance of about 0.15, while some of the marking standards had probability of noncompliance exceeding 0.85. These standards may be associated with higher risk levels if they were followed by drivers. As well, PSD risk levels were not consistent for different design speeds, since they underestimate operating speed at some locations. Llorca et al., 2014 3 INTRODUCTION Several researchers have noted that existing design guides provide a deterministic approach for

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Section: Discussionmentioning

confidence: 99%

Sight Distance Standards Based on Observational Data Risk Evaluation of Passing

Llorca

Moreno

Sayed

et al. 2014

Transportation Research Record

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“…Richl and Sayed [4] applied First-Order Reliability Method (FORM) to evaluate the safety risk of narrow medians combined with tight horizontal curves. Regarding sampling methods, Khoury and Hobeika [34] used Monte Carlo simulation to estimate the risk level of passing maneuvers based on the probability of inadequate passing sight distance (PSD) and the consequence of a collision. Sarhan and Hassan [35] used Monte Carlo simulation to estimate the probability of noncompliance for three-dimension sight distance on overlapped horizontal and vertical curves.…”

Section: Reliability Applications In Transportation Engineeringmentioning

confidence: 99%

Reliability-Based Analysis of Sight Distance Modelling for Traffic Safety

Santos-Berbel

Essa

Sayed

et al. 2017

Journal of Advanced Transportation

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Sight distance is of the utmost importance for traffic safety. The consideration of three-dimensional (3D) available sight distance (ASD) in geometric design has been supported by several researchers. However, existing ASD estimation methods are two-dimensional (2D) in nature, which do not evaluate varying visibility conditions. This paper compares different methodologies of modelling the ASD. The ASD of 402 horizontal curves, located in twelve in-service two-lane rural highways, was analyzed. Three ASD estimation methods were used which include a 2D method and two different 3D methods. The ASD results obtained through 2D and 3D methodologies are compared. Also, the different conditions of the existing roadside features or geometric elements, under which the 3D ASD estimation is important, were identified. Next, reliability theory is utilized to evaluate the risk level (probability of noncompliance,Pnc) associated with limited sight distance for each ASD modelling method. The results of the comparison emphasized the importance of considering the 3D modelled sight distance when evaluating the associated risk either in highway design or during the service life. In addition, the results indicated that the ASD modelling approach can have a significant impact on the estimation of the safety of highway design.

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“…These studies adopted a behavioural approach to understand drivers' gap-acceptance decisions and the factors that influence these decisions [14,15,18,19]. Other studies focused on: classification of overtaking maneuvers [13], evaluation of the overtaking sight distance [20,21], evaluation of the risk associated with various overtaking sight distance lengths [22], estimation of overtaking duration and distance [16,23,24], overtaking intentions [25,26], impact of drivers' age and gender [27,28], evaluation of overtaking rates, operational effectiveness of overtaking zones, and capacities [17, 29,30], and the design of overtaking assistance systems [9]. However, none of the previous studies have focused on understanding the conditions that lead drivers to abort overtaking maneuvers, and the characteristics of these aborted maneuvers.…”

Section: Introductionmentioning

confidence: 99%

When Do Drivers Abort an Overtaking Maneuver on Two-Lane Rural Roads?

Farah

2016

Transportation Research Record

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Assessing the Risk in the Design of Passing Sight Distances

Cited by 37 publications

References 3 publications

Sight Distance Standards Based on Observational Data Risk Evaluation of Passing

Sight Distance Standards Based on Observational Data Risk Evaluation of Passing

Reliability-Based Analysis of Sight Distance Modelling for Traffic Safety

When Do Drivers Abort an Overtaking Maneuver on Two-Lane Rural Roads?

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