scholarly journals Modeling and Application of Pedestrian Safety Conflict Index at Signalized Intersections

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Wei Cheng ◽  
Ning Zhang ◽  
Wei Li ◽  
Jianfeng Xi
Keyword(s):  
Safety Evaluation ◽  
Pedestrian Safety ◽  
Evaluation Study ◽  
Signalized Intersections ◽  
Safety Level ◽  
Intersection Safety ◽  
Road Users ◽  
Traffic Conflict ◽  
Vulnerable Road Users ◽  
The City

Traffic conflict between turning vehicles and pedestrians is the leading cause of pedestrian fatalities at signalized intersections. In order to provide a solution for evaluating intersection safety for vulnerable road users, this paper first determines the most important factors in analyzing pedestrian-vehicle conflict and puts forward a pedestrian safety conflict index (SCI) model to establish a quantitative standard for safety evaluation of two- or multiphase intersections. A safety level system is then designed based on SCI to help categorize and describe the safety condition of intersections applicable to the model. Finally, the SCI model is applied to the evaluation of two intersections in the city of Changchun, the result of which complies with expectation, indicating the model’s potential in providing an improved approach for pedestrian-vehicle conflict evaluation study.

scholarly journals Method for Pedestrian Crossing Risk Assessment and Safety Level Determination: the Case Study of Tallinn

2016 ◽  
Author(s):  
Maria Pashkevich ◽  
Anna Krasilnikova ◽  
Dago Antov
Keyword(s):  
Traffic Accidents ◽  
Road Traffic ◽  
Risk Level ◽  
Safety Level ◽  
Road Users ◽  
Vulnerable Road Users ◽  
Pedestrian Crossing ◽  
The City ◽  
Traffic Measurements

Pedestrians are a part of vulnerable road users which safety requires a special attention. Official statistics in Estonia from the last decade returns the following numbers: around 30 % of all road traffic accidents in the country were accidents with pedestrians, 32 % of all traffic fatalities were finished with pedestrian death. Pedestrian crossing has the biggest risk level between all kinds of pedestrian facilities, because it includes a direct conflict point between vehicle and pedestrian traffics. The article presents a method to assess risk of pedestrian crossing users and to determine safety level of this road infrastructure element. This approach is based on observation and collection of infrastructural as well as traffic data, which includes: (1) information about each pedestrian crossing facility, its location and state, (2) data about accidents with pedestrians and their features, (3) data from road traffic measurements. The main advantages of the described method are universality and comprehensiveness. The case study was done in Kristiine district of the city Tallinn, which was chosen as the most typical average district of Estonian capital. Results of this study are also presented in the article.DOI: http://dx.doi.org/10.4995/CIT2016.2016.4124

scholarly journals Safety evaluation of left-turn priority phasing at Toronto intersections

2021 ◽  
Author(s):  
Anwarul Haq Dogar
Keyword(s):  
Traffic Safety ◽  
Traffic Accidents ◽  
Safety Evaluation ◽  
Vital Role ◽  
Signalized Intersections ◽  
Side Impact ◽  
Empirical Bayesian ◽  
Left Turn ◽  
Safety Performance Functions ◽  
The City

Traffic accidents cause a huge loss to the society. According to statistics, 50% of all accidents occur at urban intersections and 47% of these are due to left-turn collisions. Countermeasure Implementation at these locations therefore can play a vital role in the improvement of traffic safety. This study illustrates a methodology for evaluation of urban 4-legged signalized intersections treated with left-turn priority phasing. The methodology is applied to three important collisions types: those due to left-turn collisions; those due to left-turn side impact collisions; and all impact types combined collisions. Data used in this analysis were obtained from the City of Toronto. Safety Performance Functions for left-turn and all impact types combined collisions which were developed by the City of Toronto, were calibrated and used in an empirical Bayesian methodology that was employed to estimate the expected frequency of accidents occurring at each intersection in order to evaluate the effectiveness of left-turn priority phasing in reducing this frequency. The results revealed that left-turn priority phasing can be an effective treatment for addressing and reducing the number of collision at signalized intersections. Flashing advance green phasing is more effective in improving safety for two of three types; all left-turn and all impact types combined collisions. Left-turn green arrow (protected/permissive) phasing is more effective for left-turn side impact collisions. By implementing this type of treatment, the number of crashes and the associated monetary loss to society could be significantly reduced.

scholarly journals Safety evaluation of left-turn priority phasing at Toronto intersections

2021 ◽  
Author(s):  
Anwarul Haq Dogar
Keyword(s):  
Traffic Safety ◽  
Traffic Accidents ◽  
Safety Evaluation ◽  
Vital Role ◽  
Signalized Intersections ◽  
Side Impact ◽  
Empirical Bayesian ◽  
Left Turn ◽  
Safety Performance Functions ◽  
The City

Traffic accidents cause a huge loss to the society. According to statistics, 50% of all accidents occur at urban intersections and 47% of these are due to left-turn collisions. Countermeasure Implementation at these locations therefore can play a vital role in the improvement of traffic safety. This study illustrates a methodology for evaluation of urban 4-legged signalized intersections treated with left-turn priority phasing. The methodology is applied to three important collisions types: those due to left-turn collisions; those due to left-turn side impact collisions; and all impact types combined collisions. Data used in this analysis were obtained from the City of Toronto. Safety Performance Functions for left-turn and all impact types combined collisions which were developed by the City of Toronto, were calibrated and used in an empirical Bayesian methodology that was employed to estimate the expected frequency of accidents occurring at each intersection in order to evaluate the effectiveness of left-turn priority phasing in reducing this frequency. The results revealed that left-turn priority phasing can be an effective treatment for addressing and reducing the number of collision at signalized intersections. Flashing advance green phasing is more effective in improving safety for two of three types; all left-turn and all impact types combined collisions. Left-turn green arrow (protected/permissive) phasing is more effective for left-turn side impact collisions. By implementing this type of treatment, the number of crashes and the associated monetary loss to society could be significantly reduced.

scholarly journals PEDESTRIAN SAFETY EVALUATION OF SIGNALIZED INTERSECTIONS USING SURROGATE SAFETY MEASURES

Transport ◽  
2020 ◽  
Vol 35 (1) ◽  
pp. 48-56
Author(s):  
Sankaran Marisamynathan ◽  
Perumal Vedagiri
Keyword(s):  
Safety Evaluation ◽  
Pedestrian Safety ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Mixed Traffic ◽  
Model Framework ◽  
Safety Measures ◽  
Severity Level ◽  
Traffic Conditions ◽  
Surrogate Safety Measures

The large proportions of pedestrian fatalities led researchers to make the improvements of pedestrian safety at intersections. Thus, this paper proposes a methodology to evaluate crosswalk safety at signalized intersections using Surrogate Safety Measures (SSM) under mixed traffic conditions. The required pedestrian, traffic, and geometric data were extracted based on the videographic survey conducted at signalized intersections in Mumbai (India). Post Encroachment Time (PET) for each pedestrian were segregated into three categories for estimating pedestrian–vehicle interactions and Cumulative Frequency Distribution (CDF) was plotted to calculate the threshold values for each interaction severity level. The Cumulative Logistic Regression (CLR) model was developed to predict the pedestrian mean PET values in the cross-walk at signalized intersections. The proposed model was validated with a new signalized intersection and the results were shown that the proposed PET ranges and model appropriate for Indian mixed traffic conditions. To assess the suitability of model framework, model transferability was carried out with data collected at signalized intersection in Kolkata (India). Finally, this study can be helpful to rank the severity level of pedestrian safety in the crosswalk and improve the existing facilities at signalized intersections.

scholarly journals Predicting Critical Bicycle-Vehicle Conflicts at Signalized Intersections

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Alireza Darzian Rostami ◽  
Anagha Katthe ◽  
Aryan Sohrabi ◽  
Arash Jahangiri
Keyword(s):  
Prediction Models ◽  
Model Performance ◽  
Safety Evaluation ◽  
Signalized Intersections ◽  
Video Data ◽  
Sustainable Transportation ◽  
Support Vector ◽  
Monitoring Period ◽  
Crash Data ◽  
Intersection Safety

Continuous development of urban infrastructure with a focus on sustainable transportation has led to a proliferation of vulnerable road users (VRUs), such as bicyclists and pedestrians, at intersections. Intersection safety evaluation has primarily relied on historical crash data. However, due to several limitations, including rarity, unpredictability, and irregularity of crash occurrences, quantitative and qualitative analyses of crashes may not be accurate. To transcend these limitations, intersection safety can be proactively evaluated by quantifying near-crashes using alternative measures known as surrogate safety measures (SSMs). This study focuses on developing models to predict critical near-crashes between vehicles and bicycles at intersections based on SSMs and kinematic data. Video data from ten signalized intersections in the city of San Diego were employed to train logistic regression (LR), support vector machine (SVM), and random forest (RF) models. A variation of time-to-collision called T2 and postencroachment time (PET) were used to specify monitoring periods and to identify critical near-crashes, respectively. Four scenarios were created using two thresholds of 5 and 3 s for both PET and T2. In each scenario, five monitoring period lengths were examined. The RF model was superior compared to other models in all different scenarios and across different monitoring period lengths. The results also showed a small trade-off between model performance and monitoring period length, identifying models with monitoring period lengths of 10 and 20 frames performed slightly better than those with lower or higher lengths. Sequential backward and forward feature selection methods were also applied that enhanced model performance. The best RF model had recall values of 85% or higher across all scenarios. Also, RF prediction models performed better when considering just the rear-end near-crashes with recalls of above 90%.

scholarly journals Safety evaluation of unconventional outside left-turn lane using automated traffic conflict techniques

2016 ◽  
Vol 43 (7) ◽  
pp. 631-642 ◽  
Author(s):  
Yanyong Guo ◽  
Tarek Sayed ◽  
Mohamed H. Zaki ◽  
Pan Liu
Keyword(s):  
Urban Areas ◽  
Safety Evaluation ◽  
Signalized Intersections ◽  
Video Data ◽  
Contributing Factors ◽  
Left Turn ◽  
Time To Collision ◽  
Traffic Conflicts ◽  
Traffic Conflict ◽  
The Right

The objective of this study is to evaluate the safety impacts of unconventional outside left-turn lane at signalized intersections. New designed unconventional outside left-turn lanes are increasingly used at signalized intersections in urban areas in China. The unconventional outside left-turn lane design allows an exclusive left-turn lane to be located to the right of through lanes to improve the efficiency and increase the capacity of left-turn movements. However, the design also raises some concerns regarding potential negative safety impacts. The evaluation is conducted using an automated video-based traffic conflict technique. The traffic conflicts approach provides better understanding of collision contributing factors and the failure mechanism that leads to road collisions. Traffic conflicts are automatically detected and time to collision is calculated based on the analysis of the vehicles’ positions in space and time. Video data are collected from a signalized intersection in Nanjing, China, where both traditional inside and unconventional outside left-turn lanes are installed on two intersection approaches. The other two approaches have only inside left-turn lanes. The study compared frequency and severity of conflict for left-turning vehicles as well as the percentage of vehicles involved in conflicts from the inside and outside left-turn lanes. The results show that the intersection approaches with outside left-turn lanes had considerably more conflicts compared to approaches without outside left-turn lanes. As well, the approaches with outside left-turn lanes had significantly higher conflict severity than the approaches without outside left-turn lanes. As such, it is recommended that the trade-off between the improved mobility and negative safety impact of outside left-turn lanes be carefully considered before recommending their installation.

AN INTEGRATED METHOD OF IDENTIFYING AND RANKING DANGER SPOTS FOR PEDESTRIANS ON MICROLOCATION

Transport ◽  
2012 ◽  
Vol 27 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Dalibor Pešić ◽  
Milan Vujanić ◽  
Krsto Lipovac ◽  
Boris Antić
Keyword(s):  
Research Methods ◽  
Traffic Safety ◽  
Traffic Accidents ◽  
Pedestrian Safety ◽  
Integrated Method ◽  
Advantages And Disadvantages ◽  
Road Users ◽  
Safety Improvement ◽  
Degree Of Exactness ◽  
Vulnerable Road Users

In traffic safety, various methods, procedures and techniques are adapted for traffic safety needs. Diverse methods lead to a different degree of exactness, accuracy and precision. The selection of research methods depends primarily on the research objective. Research methods most frequently applied for traffic safety include a statistical method, experiment, observation, tests, a questionnaire and interview, a comparison and analogy, etc. Each method has its advantages and disadvantages; however, a well devised combination of several methods and the reliability of research results can be increased. The problem of danger for pedestrians, as vulnerable road users, is constantly expressed and present in all regions. Therefore, special attention should be paid to pedestrian safety. To determine danger spots for pedestrians, the analyses of traffic accidents are most frequently used, which is the so called reactive approach to traffic safety improvement. Apart from the reactive approach, for the purpose of preventing traffic accidents in the future, it is necessary to combine some of the methods that can proactively indicate potential danger spots for pedestrians. This paper shows the method of identifying and ranking danger spots for pedestrians on micro locations, which incorporates the analysis of traffic accidents, the examination of the subjective attitudes of participants in traffic and the use of a conflict technique. Along with the so called ‘overlapping’ danger spots detected in the analysis of traffic accidents, danger spots detected based on the analysis of the subjective attitudes of pedestrians and drivers and danger spots detected in the conflict technique, a map of the so called objective and subjective danger spots is obtained. By eliminating all such identified danger spots, black spots as well as potential traffic accidents are removed. The method presented in this paper can be a very useful tool for decision-makers, for improving pedestrian safety on a micro location and for allocating funds.

Study on Extenics Evaluation of the Safety for Urban Road Intersections

2013 ◽  
Vol 779-780 ◽  
pp. 724-730 ◽  
Author(s):  
Wei Cheng ◽  
Man Rong Yuan ◽  
Jun Jun Zhao
Keyword(s):  
Traffic Management ◽  
Objective Assessment ◽  
Safety Evaluation ◽  
Element Model ◽  
Safety Level ◽  
Urban Road ◽  
Intersection Safety ◽  
Road Intersections ◽  
Matter Element Model ◽  
Single Objective

On the basis of the theory and method of extenics and to evaluate the safety level of urban road intersections quantitatively, those are selected that infrastructure, signal lamp, conflict rate in all 3 categories of 9 indicators, meanwhile, the matter element model of safety evaluation for urban road intersections is put forward based on extenics, and the objective assessment with multiobjects for urban road intersections safety level is transformed into the single objective decision which is convenient to be estimated and compared. Then by calculating the comprehensive correlative degree it is analyzed that each index factor has influence on intersection safety. The results of numerical analysis shows that the extension method can much better evaluate intersection safety level for improving intersection safety to provide efficient and valued basis for traffic management department to make decision.

scholarly journals Safety Level Of Pedestrian In Urban Area

2019 ◽  
Vol 24 (4) ◽  
pp. 335
Author(s):  
Prima Juanita Romadhona
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Conflict Analysis ◽  
Speed Limit ◽  
Vehicle Speed ◽  
Residential Areas ◽  
Safety Level ◽  
Road Users ◽  
Road Sign ◽  
Traffic Conflict

There are other road users who have high rates involvement as victims of accidents, namely vulnerable road users such as pedestrians. The study concern to find out the safety level and facilities of pedestrians. This study takes place within official and residential areas with high pedestrians mobility. Furthermore, traffic conflict analysis used as the method to measure the safety level of pedestrians. From the survey results, urban areas especially in study case is not equipped with safety facilities for pedestrians such as pedestrians crossing, road sign, mark, speed limit for vehicles, and 70% serious traffic conflict lead to potential accident which involving pedestrians. The result proves low safety level for pedestrians in urban area. As the recommendation, land use and innovation in pedestrians safety facilities installation is needed such as combination of zebra cross, speed limit, sign, mark, and speed hump to reduce vehicle speed when approaching the crossing facilities.Keywords: pedestrians safety, traffic conflict analysis Terdapat pengguna jalan lain yang memiliki angka keterlibatan yang tinggi sebagai korban kecelakaan, yaitu pengguna non kendaraan bermotor seperti pejalan kaki. Kajian ini mengenai tingkat pelayanan keselamatan dan fasilitas bagi pejalan kaki. Kajian ini mengambil lokasi wilayah perkantoran dan wilayah pemukiman dengan mobilitas pedestrian yang tinggi. Selanjutnya, digunakan analisis konflik lalu lintas sebagai metode pengukuran tingkat keselamatan responden. Dari hasil survey, kawasan perkotaan dalam studi kasus tidak difasilitasi dengan fasilitas keselamatan bagi pejalan kaki yaitu tidak adanya batasan kecepatan bagi kendaraan bermotor serta tetjadinya 70% konflik serius yang mengarah kepada potensi kecelakaan selama jam pengamatan yang melibatkan pejalan kaki. Diperlukan penanganan bagi keselamatan pejalan kaki yaitu pemanfaatan tata guna lahan dan pemasangan fasilitas keselamatan seperti zebra cross, pembatasan kecepatan, rambu, marka, dan speed hump untuk mengurangi kecepatan kendaraan bermotor yang akan melewati fasilitas penyeberangan. Kata Kunci: keselamatan, pejalan kaki, analisis konflik lalu lintas

Determination and Utilization of Dilemma Zone Length and Location for Safety Assessment of Rural High-Speed Signalized Intersections

2020 ◽  
Vol 2674 (4) ◽  
pp. 272-280
Author(s):  
Min-Wook Kang ◽  
Moynur Rahman ◽  
Joyoung Lee
Keyword(s):  
High Speed ◽  
Red Light ◽  
Signalized Intersections ◽  
Percentage Error ◽  
Traffic Operations ◽  
Safety Level ◽  
Zone Length ◽  
Dilemma Zone ◽  
Intersection Safety ◽  
Traffic Conflicts

The objective of the present study is to see how the dilemma zone length and location are related to intersection safety at rural high-speed signalized intersections. For that, dilemma zones at 30 rural signalized intersection approaches where similar traffic operations and land-use conditions are present were identified, and traffic conflicts associated with the dilemma zones were investigated. Drivers’ stop or go behaviors as well as vehicle dynamics (e.g., vehicle speeds and locations) during the yellow and red clearance intervals were collected and analyzed to determine the dilemma zone length and location of each site. Red-light running violations and vehicles’ abrupt stops were also collected to investigate the relationship between such conflicts and dilemma zone length and location. As a result, two dilemma zone conflict models were developed. The analysis results show that the conflict models are accurate enough to predict the safety level of high-speed signalized intersections using the two dilemma zone variables. Results show that the chance of intersection angle conflicts increases if the dilemma zone is located farther from the intersection stop bar. Results also show that there would be a high chance of rear-end conflicts if the dilemma zone length is longer. The models were validated with additional datasets, and acceptable root means square error and mean absolute percentage error values were obtained as a result.

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