Understanding Factors Affecting Frequency of Traffic Conflicts between Electric Bicycles and Motorized Vehicles at Signalized Intersections

2015 ◽  
Vol 2514 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Lu Bai ◽  
Pan Liu ◽  
Yanyong Guo ◽  
Chengcheng Xu
Keyword(s):  
Signalized Intersections ◽  
Factors Affecting ◽  
Traffic Conflicts ◽  
Electric Bicycles ◽  
Motorized Vehicles

Analysis of Pedestrian Conflicts with Left-Turning Traffic

1996 ◽  
Vol 1538 (1) ◽  
pp. 61-67 ◽  
Author(s):  
Dominique Lord
Keyword(s):  
Data Collection ◽  
Statistical Tests ◽  
Computer Programs ◽  
Signalized Intersections ◽  
Laptop Computer ◽  
Expected Number ◽  
Positive Correlation ◽  
Data Collection Process ◽  
Traffic Conflicts ◽  
Traffic Conflict

The interaction between pedestrians and left-turning vehicles at signalized intersections are examined using the traffic conflict technique. Paramount was a comparison of the safety of left turns at two types intersections: T-intersections and X-intersections (cross-intersections). Previous research has indicated that T-intersections are more dangerous to pedestrians. In preparation for the comparison several traffic conflict definitions and their applications to pedestrians were evaluated. Use of a laptop computer for data collection was tested. Eight sites taken from intersections in Hamilton, Ontario, Canada, were selected. A conflict recording methodology was developed for T-intersections and X-intersections that consisted of recording data at various times along the paths of pedestrians and left-turning vehicles, and recording traffic conflicts. Two computer programs were written for the data collection process: one for vehicles and one for pedestrians. Several statistical tests to relate traffic conflicts and the expected number of accidents were performed. These tests indicate that a positive correlation between traffic conflicts and expected number of accidents exists; they also suggest that T-intersections have a higher traffic conflict rate than X-intersections.

scholarly journals Comparison of Crash Severity Risk Factors at Signalized and Stop-Controlled Intersections in Urban and Rural Areas in Alabama

2018 ◽  
Vol 7 (5) ◽  
pp. 50
Author(s):  
Sumalatha Kesavareddy ◽  
Kirolos Haleem ◽  
Mehrnaz Doustmohammadi ◽  
Michael Anderson
Keyword(s):  
Traffic Control ◽  
Rural Areas ◽  
Signalized Intersections ◽  
Crash Severity ◽  
Factors Affecting ◽  
Side Impacts ◽  
Binary Logit ◽  
Urban And Rural Areas ◽  
New Variables ◽  
Significant Factors

Understanding the factors that affect crash severity at intersections is essential to develop strategies to alleviate safety deficiencies. This paper identifies and compares the significant factors affecting crash severity at signalized and stop-controlled intersections in urban and rural areas in Alabama using recent five-year crashes. A random forest model was used to rank variable significance and a binary logit model was applied to identify the significant factors at both intersection types in urban and rural areas. Four separate models (urban signalized, urban stop-controlled, rural signalized, and rural stop-controlled) were developed. New variables that were not previously explored were used in this study, such as the roadway type (one-way vs. two-way) and traffic control functioning (yes or no). It was found that one-way roadways were associated with a reduction in crash severity at urban signalized intersections. In all four models, rear-end crashes showed lesser severity than side impacts. Head-on crashes, higher speed limits, and curved sections showed higher severity in urban signalized and stop-controlled intersections. In rural stop-controlled intersections, right-turning maneuvers had a severity reduction. Female drivers showed 15% and 45% higher severity likelihood (compared to males) at urban and rural signalized intersections, respectively. Strategies to alleviate crash severity are proposed.

scholarly journals Random Parameter Negative Binomial Model of Signalized Intersections

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Minho Park ◽  
Dongmin Lee ◽  
Jinwoo Jeon
Keyword(s):  
Negative Binomial ◽  
Random Parameter ◽  
Signalized Intersections ◽  
Negative Binomial Model ◽  
Marginal Effect ◽  
Binomial Model ◽  
Random Parameters ◽  
Factors Affecting ◽  
Independent Variables ◽  
Insight Into

Factors affecting accident frequencies at 72 signalized intersections in the Gyeonggi-Do (province) over a four-year period (2007~2010) were explored using the random parameters negative binomial model. The empirical results from the comparison with fixed parameters binomial model show that the random parameters model outperforms its fixed parameters counterpart and provides a fuller understanding of the factors which determine accident frequencies at signalized intersections. In addition, elasticity and marginal effect were estimated to gain more insight into the effects of one-percent and one-unit changes in the dependent variable from changes in the independent variables.

scholarly journals Exploring Factors Impacting Paths of Left-Turning Vehicles from Minor Road Approach at Unsignalized Intersections

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Guoqiang Zhang ◽  
Yuli Qi ◽  
Jun Chen
Keyword(s):  
Traffic Safety ◽  
Major Road ◽  
Traffic Crashes ◽  
Factors Affecting ◽  
Traffic Efficiency ◽  
Logistic Analysis ◽  
Unsignalized Intersections ◽  
Minor Road ◽  
Traffic Conflicts ◽  
Probability Prediction

At unsignalized intersections, left-turning vehicles from minor road approach are more likely to be involved in traffic conflicts and traffic crashes and are one of the most leading factors impacting traffic efficiency and capacity. The authors of the paper observed that some drivers behaved illegally and dangerously while performing left turns from minor road approach, resulting in abnormal trajectories at unsignalized intersections. By applying binary logistic analysis, a probability prediction model was developed to explore various factors affecting probability of normal path taken by drivers while turning left from minor road approach. Based upon the model, measures such as lowering running speeds of vehicles on major road or minor road and adding more lanes on minor road can be used to encourage more drivers to take normal vehicle paths, which is helpful for the improvement of traffic safety, efficiency, and capacity. Results of the paper can be used for the guidance of design and management of unsignalized intersections.

A review of methodological approaches for saturation flow estimation at signalized intersections

2020 ◽  
Vol 47 (3) ◽  
pp. 237-247 ◽  
Author(s):  
Satyajit Mondal ◽  
Ankit Gupta
Keyword(s):  
Influencing Factors ◽  
Discharge Rate ◽  
Estimation Procedure ◽  
Signalized Intersections ◽  
Signalized Intersection ◽  
Factors Affecting ◽  
Flow Estimation ◽  
Soft Computing Techniques ◽  
Methodological Approaches ◽  
Saturation Flow

The estimation of the saturation flow is the utmost component for performance evaluation of a signalized intersection. The flow rate estimation procedure includes the analysis of the vehicles headway, vehicles discharge rate, passenger car unit, effective green time and cycle length of the signalling system. This study attempts to exhaustively review the existing literature and its suitability along with the multiple factors affecting the performance of signalized intersection. Different methodological approaches and soft computing techniques used worldwide by the researchers both in developed and developing countries are emphasized. This study also highlights the several influencing factors that have a significant impact on saturation flow value and several methodological approaches to determine the flow value through normalizing the influencing factors, which lead to a better way for planning and designing of a signalized intersection.

scholarly journals Using Cellular Automata to Investigate Pedestrian Conflicts with Vehicles in Crosswalk at Signalized Intersection

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Xiaomeng Li ◽  
Xuedong Yan ◽  
Xingang Li ◽  
Jiangfeng Wang
Keyword(s):  
Cellular Automata ◽  
Signalized Intersections ◽  
Influential Factors ◽  
Urban Traffic ◽  
Signalized Intersection ◽  
Signal Timing ◽  
Cellular Automata Model ◽  
Intersection Safety ◽  
Traffic Conflicts ◽  
Simulation Results

The operational efficiency and safety of pedestrian flows at intersections is an important aspect of urban traffic. Particularly, conflicts between pedestrians and vehicles in crosswalk are one of the most influential factors for intersection safety. This paper presents a cellular automata model that simulates pedestrian and vehicle crossing behaviors at signalized intersections. Through the simulation, we investigate the effects of different pedestrian signal timing and crosswalk widths on the crosswalk capacity, the number of traffic conflicts between pedestrians and vehicles, and pedestrian delay due to the conflicts. The simulation results indicate that the cellular automata is an effective simulation platform for investigating complex pedestrian-related traffic phenomenon at signalized intersections.

Correlation Model between Speed and Density of Electric Bicycles at Signalized Intersections

2015 ◽  
Vol 744-746 ◽  
pp. 1803-1807
Author(s):  
Jia Jun Shen ◽  
Qun Wang ◽  
Zhi Ming Cao
Keyword(s):  
Linear Function ◽  
Data Fitting ◽  
Signalized Intersections ◽  
Correlation Model ◽  
Theoretical Support ◽  
Electric Bicycles

In order to explore the characteristics of electric bicycles at urban intersections, the model between speed and density was developed. Coordinates of electric bicycles were obtained based on photogrammetry, and 85% riding width was proposed to be the design width through the analysis of relationship between cycle volume and riding width. In addition, the model between speed and density were obtained through data fitting, which was almost a linear function. The speed and riding width can be obtained through the model on the basis of the volume of electric bicycles, which can provide theoretical support for the control and design of urban intersections..

Leading Pedestrian Intervals

2017 ◽  
Vol 2620 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Anuj Sharma ◽  
Edward Smaglik ◽  
Sirisha Kothuri ◽  
Oliver Smith ◽  
Peter Koonce ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
Signalized Intersections ◽  
Crash Data ◽  
Trade Offs ◽  
Quantitative Metrics ◽  
Traffic Conflicts ◽  
Before And After ◽  
Economic Analyses ◽  
Benefit Cost

To improve the safety of people walking at particular signalized intersections, traffic signal engineers may implement leading pedestrian intervals (LPIs) to provide pedestrians with a walk signal for a few seconds before the parallel vehicular green indication. Previous before-and-after studies and simple economic analyses have indicated that LPIs are low-cost tools that can reduce vehicle–pedestrian conflicts and crashes at some signalized intersections. Despite this evidence, municipalities have little guidance for when to implement LPIs. A marginal benefit–cost framework is developed with quantitative metrics and extends the concept of traffic conflicts and marginal safety–delay trade-offs to analyze the appropriateness of implementing an LPI at specific signalized intersections. The method provides guidance to help quantify the probability of a conflict occurring and direction on whether to implement an LPI at a given location from macroscopic-level inputs, including number of turning movements, crash data, and geometry. A case study with sample data indicated that an LPI was cost-effective for the scenario presented.

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.

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