scholarly journals A Safety Evaluation Model of Intersections under Mixed Traffic Conditions Using Traffic Conflicts and Cloud Model

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xuan Can Vuong ◽  
Rui-Fang Mou ◽  
Trong Thuat Vu ◽  
Van Hung Tran ◽  
Chi Trung Nguyen

Safety evaluation of traffic conflict is a very important and challenging issue in evaluating intersection safety under incomplete traffic accident data conditions and is also one of the main safety surrogate measures of analyzing accident data recently. It helps to analyze and solve intersection problems comprehensively and deeply. From there, it helps to improve traffic safety as well as reduce the risk of traffic accidents at intersections. Various evaluation methods based on traffic conflict have been proposed to make conflict safety levels at intersections more consistent and objective. However, a major concern is that many existing measurements are still subjective and are not easy to obtain uniformly. This study aimed to develop a model for safety evaluation at intersections in a comprehensive way that may be expected to directly link to the severity of the accident from different evaluation indicators. First, the three factors, including time to collision (TTC), conflicting speed (CS), and deceleration rate (DR) to avoid a crash, are introduced into safety evaluation of conflicts as the indicators. And then, as regards the fuzziness and randomness of the evaluation indicators, the qualitative concept has to be converted into a quantitative one utilizing cloud model, which implements the natural transformation between the qualitative concept of the safety level of traffic conflict and the membership degree of the evaluation indicators corresponding to the different safety levels. Finally, an indicator weight model is built based on the information entropy and the AHP method to determine the safety level. We illustrate the practical implementation of the proposed method using actual data of a typical signalized intersection from Hanoi City of Vietnam. The results indicate that traffic conflict analyzed by the proposed method was appropriate with actual state of the intersection, and the proposed method is simple, effective, and feasible, so it has a certain application value.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Li Yuan ◽  
He-wei Yuan ◽  
Yong-feng Ma ◽  
Ying-wei Ren

Provincial highway safety is one of the most important issues in transportation. To evaluate or assess the safety performance of provincial highway, traffic crash analysis or traffic conflict analysis has been used for a long history. However, it is very difficult and time-consuming to obtain historical crash data or traffic conflict data. This study analyzes the provincial highways' accident data during 2006–2010, and the characteristics of provincial highway have been investigated; in addition the influencing elements are identified. A comprehensive approach is introduced to evaluate provincial highway safety performance and corresponding models are developed considering the accidents, geometrics, facilities, and traffic environment. The approach will also result in a safety index to indicate the safety performance level of the provincial highway. In this paper, the approach (called safety evaluation approach) is practically applied to evaluate the safety performance of some provincial highways in Hebei Province. Results from the real application indicate that the approach has good applicability and can be used by field safety engineers.



2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ruoxi Jiang ◽  
Shunying Zhu ◽  
Pan Wang ◽  
QiuCheng Chen ◽  
He Zou ◽  
...  

Currently, many studies on the severity of traffic conflicts only considered the possibility of potential collisions but ignored the consequences severity of potential collisions. Aiming toward this defect, this study establishes a potential collision (serious conflict) consequences severity model on the basis of vehicle collision theory. Regional vehicles trajectory data and historical traffic accident data were obtained. The field data were brought into the conflict consequences severity model to calculate the conflict severity rate of each section under different TTC thresholds. For comparison, the traditional conflict rate of each section under different TTC thresholds that considered only the number of conflicts was also calculated. Results showed that the relationship between conflict severity rate and influencing factors was somehow different. The conflict severity rate seemed to have a higher correlation with accident rate and accident severity rate than conflict rate did. The TTC threshold value also affected the correlation between conflicts and accidents, with high and low TTC threshold indicating a lower correlation. The results showed that conflict severity rate that considered each single conflict consequence severity was a little better than the traditional conflict rate that considered only the numbers of conflicts in reflecting real risks as a new conflict evaluation indicator. The severity of traffic conflicts should consider two dimensions: the possibility and consequence of potential collisions. Based on this, we propose a new traffic safety evaluation method that takes into account the severity of the consequences of the conflict. More data and prediction models are needed to conduct more realistic and complex research in the future to ensure reliability of this new method.



2012 ◽  
Vol 588-589 ◽  
pp. 2117-2120
Author(s):  
Jian Feng Xi ◽  
Zhen Hai Gao ◽  
Bo Qi ◽  
Hai Zhu Liu

Curved section is one of the sections where happened extraordinarily serious traffic accidents in China. Until now, one kind of the traffic safety evaluation method based on the accident indexes, the other based on the non-accident indexes, just as the traffic conflict technique. But there are difficulties in collecting data when the evaluation of traffic safety on specific road sections is applied. So, one safety evaluation method for the curved sections is putting forward, in which the deviation value between the driving track and safe trajectory is used as the evaluation index, and the gray evaluation method is applied. The case study shows that, the method in this paper could be a new way for traffic safety evaluation.



2014 ◽  
Vol 1065-1069 ◽  
pp. 3320-3324
Author(s):  
Rui Li ◽  
Zhi Peng Ge

The severity of accidents can show the dangerous of intersections directly, however, the safety of intersections which have not accident data could not be evaluated easily. This paper introduced “Intersection Dangerous Parameter (IDP)” model to quantify intersections’ safety. Because IDP is calculated based on Intersection Conflict Dangerous Parameter (ICDP) and Intersection Accident Dangerous Parameter (IADP), IDP model can help to evaluate the safety of intersections which have not accident data. Rely on Chinese and American data, IDP model is calibrated and the safeties of three type intersections are evaluated using this method.



2016 ◽  
Vol 845 ◽  
pp. 394-403 ◽  
Author(s):  
Fardzanela Suwarto ◽  
Kami Hari Basuki

The majority of traffic safety evaluations in the world generally have been conducted by colecting historical accident data. The data will then being analyzed using risk prediction models or before-after study that required an exact and reliable data. Meanwhile, the availability of accident data is rare where the rest actually consist of near-crashes and abnormal behaviour, which is mostly underreporting and lack of detail concerning the behavioural and situational of the event. Therefore, traffic conflict technique, is needed to assess traffic safety as another approach rather than waiting for several years until a number of accidents happen in a certain area. Hence the aim of this study is to make a safety evaluation towards a specific intersection in Hasselt Belgium using traffic conflict technique. The observation of conflict (near crashes) was carried out in intersection of Manteliusstraat – Dorpsstraat – Thonissenlaan in the Hasselt, Belgium. In order to differentiate slight conflict and serious conflict, the TA-value (Time of accident) was defined based on the estimated speed of the road user and estimated distance from the road user when conflict occurred. From the observation, it was found that the conflicts between car and pedestrian were the most frequent conflict, with 50% of the total conflict, and that the conflict between car with car and the conflict between car with cyclist were high in terms of severity level based on the TA-value. By taking these into consideration, it can be concluded that unsafe crossing for pedestrian and cyclist, different speed, and peak hour traffic were the causes of conflict. Therefore, it was concluded that traffic conflict technique can be used to assess and measure traffic safety in a certain road segment. Furthermore, in term of safety, the Manteliusstraat – Dorpsstraat – Thonissenlaan intersection should be modified with some alternatives; signalized intersection with toucan crossing and traffic control devices improvement



2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Guozhu Cheng ◽  
Lixin Wu ◽  
Liang Xu ◽  
Lihui Qin ◽  
Yuxia Wang

Overtaking experiments on four two-lane highways were conducted. The data of overtaking conflict time (the time difference between the time of driving back to the original lane and the time of meeting with the first opposing vehicle) and experimental drivers’ risk feeling were observed. Membership was adopted to denote the experimental drivers’ risk feelings which also denote the severity of traffic conflict. Membership ranges from 0 to 1 and corresponding risk becomes higher; that is, traffic conflict becomes more serious. According to the observed relationship between overtaking conflict time, and drivers’ risk feeling membership, Cauchy distribution function was adopted as membership function. The thresholds of the severity of traffic conflict were determined through Delphi method. The relationship model among traffic volume, overtaking conflict time and design speed was established according to experimental data. Then the idea of setting auxiliary lane on two-lane highway in China was presented. And the traffic volume values that need setting auxiliary lane corresponding to different design speed and traffic conflict degree were given according to the established model. It is expected to improve the traffic safety level of two-lane highway in China through setting auxiliary lane.



2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lei Lin ◽  
Feng Shi ◽  
Weizi Li

AbstractCOVID-19 has affected every sector of our society, among which human mobility is taking a dramatic change due to quarantine and social distancing. We investigate the impact of the pandemic and subsequent mobility changes on road traffic safety. Using traffic accident data from the city of Los Angeles and New York City, we find that the impact is not merely a blunt reduction in traffic and accidents; rather, (1) the proportion of accidents unexpectedly increases for “Hispanic” and “Male” groups; (2) the “hot spots” of accidents have shifted in both time and space and are likely moved from higher-income areas (e.g., Hollywood and Lower Manhattan) to lower-income areas (e.g., southern LA and southern Brooklyn); (3) the severity level of accidents decreases with the number of accidents regardless of transportation modes. Understanding those variations of traffic accidents not only sheds a light on the heterogeneous impact of COVID-19 across demographic and geographic factors, but also helps policymakers and planners design more effective safety policies and interventions during critical conditions such as the pandemic.



ICCTP 2011 ◽  
2011 ◽  
Author(s):  
Jianxiao Ma ◽  
Taowei Yan ◽  
Li Lin ◽  
Jingwen Jiang


2018 ◽  
Vol 250 ◽  
pp. 02002 ◽  
Author(s):  
Nordiana Mashros ◽  
SittiAsmah Hassan ◽  
Yaacob Haryati ◽  
Mohd Shahrir Amin Ahmad ◽  
Ismail Samat ◽  
...  

Understanding and prioritising crash contributing factors is important for improving traffic safety on the expressway. This paper aims to identify the possible contributory factors that were based on findings obtained from crash data at Senai-Desaru Expressway (SDE), which is the main connector between the western and eastern parts of Johor, Malaysia. Using reported accident data, the mishaps that had occurred along the 77.2 km road were used to identify crash patterns and their possible related segment conditions. The Average Crash Frequency and Equivalent Property Damage Only Average Crash Frequency Methods had been used to identify and rank accident-prone road segments as well as to propose for appropriate simple and inexpensive countermeasures. The results show that the dominant crash type along the road stretches of SDE had consisted of run-off-road collision and property damage only crashes. All types of accidents were more likely to occur during daytime. Out of the 154 segments, the 4 most accident-prone road segments had been determined and analysed. The results obtained from the analyses suggest that accident types are necessary for identifying the possible causes of accidents and the appropriate strategies for countermeasures. Therefore, this accident analysis could be helpful to relevant authorities in reducing the number of road accidents and the level of accident severity along the SDE.



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