Using VISSIM simulation model and Surrogate Safety Assessment Model for estimating field measured traffic conflicts at freeway merge areas

2013 ◽  
Vol 7 (1) ◽  
pp. 68-77 ◽  
Author(s):  
Rong Fan ◽  
Wei Wang ◽  
Pan Liu ◽  
Hao Yu
Keyword(s):  
Simulation Model ◽  
Safety Assessment ◽  
Assessment Model ◽  
Traffic Conflicts

scholarly journals Safety Evaluation of Turbo-Roundabouts with and without Internal Traffic Separations Considering Autonomous Vehicles Operation

2021 ◽  
Vol 13 (16) ◽  
pp. 8810
Author(s):  
Tullio Giuffrè ◽  
Anna Granà ◽  
Salvatore Trubia
Keyword(s):  
Autonomous Vehicles ◽  
Safety Assessment ◽  
Safety Evaluation ◽  
Simulation Models ◽  
Safety Performance ◽  
Assessment Model ◽  
Crash Data ◽  
Vehicle Trajectories ◽  
Traffic Conflicts ◽  
Surrogate Measures

The paper presents a microsimulation approach for assessing the safety performance of turbo-roundabouts where Cooperative Autonomous Vehicles “CAVs” have been introduced into the traffic mix alongside conventional vehicles “CVs”. Based on the analysis of vehicle trajectories from VISSIM and subsequent analysis of traffic conflicts through the Surrogate Safety Assessment Model (SSAM), the research aims to evaluate the safety benefits of turbo-roundabouts where the lanes are physically separated by raised curbs, compared to roundabouts without such curbs. The paper will then describe the methodological path followed to build VISSIM models of turbo-roundabouts with and without raised curbs in order to calibrate the simulation models and estimate the potential conflicts when a higher percentage of CAVs are introduced into the traffic mix. A criterion has been also proposed for setting properly the principal SSAM filters. The results confirmed both higher safety levels for turbo-roundabouts equipped with raised lane dividers compared to turbo-roundabout solutions without curbs, and better safety conditions under the traffic mix of CVs and CAVs. Therefore, it follows that, in absence of crash data including CAVs, the surrogate measures of safety are the only approach in which the safety performance of any roundabout or road entity can be evaluated.

Comparison between Surrogate Safety Assessment Model and Real-Time Safety Models in Predicting Field-Measured Conflicts at Signalized Intersections

2020 ◽  
Vol 2674 (3) ◽  
pp. 100-112 ◽  
Author(s):  
Mohamed Essa ◽  
Tarek Sayed
Keyword(s):  
Real Time ◽  
Safety Assessment ◽  
Traffic Simulation ◽  
Simulation Models ◽  
Signalized Intersections ◽  
Assessment Model ◽  
Vehicle Trajectories ◽  
Traffic Conflicts ◽  
Safety Models ◽  
Conflict Prediction

Traffic simulation models are frequently used to evaluate the safety of signalized intersections, especially when testing unconventional designs or investigating the effects of emerging technologies such as connected and autonomous vehicles. In this approach, vehicle trajectories extracted from traffic simulation are usually analyzed using the surrogate safety assessment model (SSAM) to estimate the number and severity of traffic conflicts. However, recent research has shown that evaluating safety using SSAM has several limitations. First, a rigorous calibration procedure must be applied to the simulation model to obtain reliable conflict results. Second, simulation models in many cases do not accurately represent actual driving behavior. Subsequently, they often fail to capture the actual mechanisms generating near-misses. This paper presents a new procedure, alternative to SSAM, for evaluating the safety of signalized intersections. The procedure combines simulated vehicle trajectories with real-time safety models to predict rear-end conflicts. The conflict prediction is based on dynamic traffic parameters, such as traffic volume and shock wave characteristics, repeatedly measured over a short time interval (a few seconds). To validate the proposed procedure, its performance was investigated in predicting traffic conflicts extracted from 54 hours of real-world video data at two signalized intersections in the city of Surrey, British Columbia. The predicted conflict results were compared with SSAM. Overall, the results showed that the proposed procedure outperforms SSAM in relation to accuracy of conflict prediction. Lastly, a case study of using the proposed procedure in evaluating the safety impact of a recently developed connected-vehicles application is presented.

Safety Assessment Method for Equipment of Urban Rail Transit Network Operation

2014 ◽  
Vol 513-517 ◽  
pp. 3958-3963 ◽  
Author(s):  
Bo Gao ◽  
Ling Xi Zhu ◽  
Xue Mei Xiao
Keyword(s):  
Safety Assessment ◽  
Spatial Information ◽  
Urban Rail Transit ◽  
Assessment Model ◽  
Rail Transit ◽  
Source Information ◽  
Transit Network ◽  
Urban Rail ◽  
Network Operation ◽  
Urban Rail Transit Network

Based on the multi-source information fusion and complex network theory, through studying the effective matching and integration of safety equipment and spatial information of urban rail transit network operation, a safety assessment model is proposed: through equipment fusion and the node fusion, the global safety parameter is obtained, which is accurate in description and evaluation of urban rail transit operating than the partial safety factors and realize the transform from microscopic description to macroscopic description.

Safety Assessment of Railway Dangerous Goods Transportation Based on Set Pair Analysis

2013 ◽  
Vol 869-870 ◽  
pp. 288-292
Author(s):  
Dong Jie Liu ◽  
Zhen Lin Wei
Keyword(s):  
Safety Assessment ◽  
Assessment Model ◽  
Engineering System ◽  
Set Pair Analysis ◽  
System Research ◽  
Analytic Hierarchy ◽  
Dangerous Goods ◽  
Index Weight ◽  
Hierarchy Process ◽  
Pair Analysis

In order to overcome the drawbacks that occur when traditional safety assessment methods do not consider the certain and uncertain characteristics of information and in order to enhance the calculation efficiency, a new Identical Discrepancy Contrary (IDC) system is safety comprehensive assessment model based on Set Pair Analysis is established. Incorporating the Analytic Hierarchy Process (AHP) to obtain the index weight, this model analyses the uncertainties in the degree of connection acquired by assessment, and then makes the identical discrepancy contrary system research on the certainty and uncertainty of information in the engineering system.

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