scholarly journals Estimation of Critical Gap Based on Raff’s Definition

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Rui-jun Guo ◽  
Xiao-jing Wang ◽  
Wan-xiang Wang
Keyword(s):  
Accurate Result ◽  
Traffic Flows ◽  
Application Field ◽  
Critical Gap ◽  
Unsignalized Intersections ◽  
Minor Road ◽  
New Models ◽  
Definition Of ◽  
Gap Acceptance Theory ◽  
Calculation Models

Critical gap is an important parameter used to calculate the capacity and delay of minor road in gap acceptance theory of unsignalized intersections. At an unsignalized intersection with two one-way traffic flows, it is assumed that two events are independent between vehicles’ arrival of major stream and vehicles’ arrival of minor stream. The headways of major stream follow M3 distribution. Based on Raff’s definition of critical gap, two calculation models are derived, which are named M3 definition model and revised Raff’s model. Both models use total rejected coefficient. Different calculation models are compared by simulation and new models are found to be valid. The conclusion reveals that M3 definition model is simple and valid. Revised Raff’s model strictly obeys the definition of Raff’s critical gap and its application field is more extensive than Raff’s model. It can get a more accurate result than the former Raff’s model. The M3 definition model and revised Raff’s model can derive accordant result.

Defining and Analyzing Forceful Gap Behavior at Unsignalized Intersections

2020 ◽  
Vol 2674 (8) ◽  
pp. 420-428
Author(s):  
Mukti Advani ◽  
Neelam J. Gupta ◽  
S. Velmurugan ◽  
Erramppalli Madhu ◽  
Satish Chandra
Keyword(s):  
Threshold Value ◽  
Base Case ◽  
Major Road ◽  
Speed Reduction ◽  
Critical Gap ◽  
Traffic Conditions ◽  
Unsignalized Intersections ◽  
Definition Of ◽  
Gap Creation ◽  
Made In

Under mixed-mode traffic conditions prevailing on Indian roads at unsignalized intersections, it is commonly observed that vehicles entering from minor streets indulge in forceful gap creation/delay for the vehicles moving on the major road. Although this driving behavior has been reported in some of the published studies for Indian traffic conditions, a clear definition of such forceful entries is not available. An attempt has been made in this study to define this forceful entry phenomenon on the basis of changes in the speed of major streets’ vehicles approaching the intersection on a typical case of mixed-traffic environs. In this regard, field observations were recorded through videography to obtain the speed reduction threshold value for categorizing an entry as a forceful entry. To quantify the above, data in relation to various vehicle types approaching intersections and their associated speeds at the reference area were extracted at the approach arms of the intersection. On the basis of observations, collected data were divided into three scenarios: ( 1 ) vehicles on major roads reduce their speed when vehicles are absent on minor roads; ( 2 ) vehicles on major roads reduce their speed when vehicles are waiting on minor roads; and ( 3 ) vehicles on major roads reduce their speed when vehicles from minor roads have accepted the gap/lag for movement. The changes in speed in all the three scenarios were compared to identify forceful entries with the base case of normal traffic flow on the major road without the existence of forceful entry phenomenon. The study revealed that the speed reduction to the extent of 73% is considered as a forceful entry at the selected location. Furthermore, the study estimated the effect of forceful behavior on critical gap at unsignalized intersections.

scholarly journals Critical Gaps at Unsignalized Intersections with Bending Right-of-Way

2018 ◽  
Vol 20 (4) ◽  
pp. 69-75
Author(s):  
Andrea Kocianova ◽  
Eva Pitlova
Keyword(s):  
Calculation Procedure ◽  
Gap Acceptance ◽  
Driver Behaviour ◽  
Critical Gap ◽  
Right Of Way ◽  
Unsignalized Intersections ◽  
Capacity Calculation ◽  
Rank 2 ◽  
Gap Acceptance Theory ◽  
Traffic Rules

The capacity calculation procedure for unsignalized intersections is based on the gap-acceptance theory in most of existing capacity regulations and it relies on one of the important parameters - critical gap. However, the capacity calculation procedure and values of critical gaps according to these regulations are valid only for intersections with standard right-of-way (major street leading straight). Nevertheless, in Slovakia, intersections with bending right-of-way (major street not leading straight, but bending) can be encountered. The specific mode of right-of-way results in different priority ranks of traffic movements (set by traffic rules of driving), more complicated traffic situation and therefore, different driver behaviour characteristics. To examine the gap acceptance behaviour of drivers under these specific conditions, an unsignalized four-leg intersection with bending right-of-way located in an urban area of Zilina, Slovakia, was selected. Three different methods (Raff, Wu, and MLM Troutbeck) were used for critical gap estimation from the field data. In the article, results of critical gaps for three through movements of different priority rank (major-street through movement of Rank 2 and minor-street through movements of Rank 3 and 4) are presented. The results show, that the values of critical gaps differ depending on the method by about 3-5 % only, which is not significant. Troutbeck ´s MLM method gives the highest values. The priority rank of movement has the greatest impact on the result. The values of critical gap for major-street through movement of Rank 2 are the smallest; they are approximately 1.3-2.1 s smaller than the values for minor-street through movements of Rank 3 or 4. The highest values of critical gap have been estimated for minor-street through movement of Rank 4 and they are higher compared to the current Slovak regulations TP 102 values for the same priority rank.

scholarly journals Dynamic Modeling of VISSIM's Critical Gap Parameter at Unsignalized Intersections

2013 ◽  
Vol 2395 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Francesco Viti ◽  
Bart Wolput ◽  
Chris M. J. Tampère ◽  
Pieter Vandervelden
Keyword(s):  
Dynamic Modeling ◽  
Critical Gap ◽  
Unsignalized Intersections ◽  
Gap Parameter

scholarly journals Modeling and Predicting Stochastic Merging Behaviors at Freeway On-Ramp Bottlenecks

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Jian Sun ◽  
Kang Zuo ◽  
Shun Jiang ◽  
Zuduo Zheng
Keyword(s):  
Los Angeles ◽  
Great Influence ◽  
Data Sets ◽  
Gap Acceptance ◽  
Trajectory Data ◽  
Logistic Regression Models ◽  
Critical Gap ◽  
Merging Behavior ◽  
The Impact ◽  
Gap Acceptance Theory

Merging behavior is inevitable at on-ramp bottlenecks and is a significant factor in triggering traffic breakdown. In modeling merging behaviors, the gap acceptance theory is generally used. Gap acceptance theory holds that when a gap is larger than the critical gap, the vehicle will merge into the mainline. In this study, however, analyses not only focus on the accepted gaps, but also take the rejected gaps into account, and the impact on merging behavior with multi-rejected (more than once rejecting behavior) gaps was investigated; it shows that the multi-rejected gaps have a great influence on the estimation of critical gap and merging prediction. Two empirical trajectory data sets were collected and analyzed: one at Yan’an Expressway in Shanghai, China, and the other at Highway 101 in Los Angeles, USA. The study made three main contributions. First, it gives the quantitative measurement of the rejected gap which is also a detailed description of non-merging event and investigated the characteristics of the multi-rejected gaps; second, taking the multi-rejected gaps into consideration, it further expanded the concept of the “critical gap” which can be a statistic one and the distribution function of merging probability with respect to such gaps was analyzed by means of survival analysis. This way could make the full use of multi-rejected gaps and accepted gaps and reduce the sample bias, thus estimating the critical gap accurately; finally, considering multi-rejected gaps, it created logistic regression models to predict merging behavior. These models were tested using field data, and satisfactory performances were obtained.

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.

Analysis and Evaluation of the Capacity of Roundabouts

1997 ◽  
Vol 1572 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Abishai Polus ◽  
Sitvanit Shmueli
Keyword(s):  
The United States ◽  
Gap Acceptance ◽  
Highway Capacity ◽  
Left Turn ◽  
Highway Capacity Manual ◽  
Explanatory Variables ◽  
Geometric Characteristics ◽  
Critical Gap ◽  
Unsignalized Intersections ◽  
German Model

Roundabouts are replacing conventional unsignalized intersections in many parts of the world and could become more widespread in the United States, although there are some limitations as well as clear advantages. Models for entry capacity into the rotary were developed. Entry capacity depends on the geometric characteristics of the roundabout, particularly the diameter of the outside circle of the intersection. The geometric characteristics determine the speed of vehicles around the central island and, therefore, have an impact on the gap-acceptance process and consequently the capacity. Traffic conditions that impede entry capacity involve the flow around the roundabout. Flow and geometric data from six small to medium-sized roundabouts were analyzed. Individual and aggregated entry-capacity models were calibrated by using the diameter and circulating flows as explanatory variables. Very good fits to the data were obtained; the results also fit models developed in other countries. The Australian model resulted in slightly higher entry capacities for moderate to low circulating flows and lower entry capacities for high circulating flows. Very close proximity to the German model was obtained, although it does not depend on the geometric characteristics of the circle. The roundabout provides an advantage over a conventional unsignalized intersection. A faithful concurrence between the model developed and the latest Highway Capacity Manual model for right-turn capacity at an unsignalized intersection is obtained if the circulating flow is replaced by the conflicting flow. The advantage of entry capacities of the roundabout over the calculated capacities of the Highway Capacity Manual left-turn model is shown. Further research is proposed to study the effect on entry capacity of two circulating lanes rather than one and the effect of the increase in circulating flows on the gap-acceptance process, particularly the reduction in critical gap at high flows.

scholarly journals PERSPECTIVES FOR DEVELOPMENT OF BLOCKCHAIN APPLICATIONS IN UKRAINE

2018 ◽  
pp. 35-48 ◽  
Author(s):  
Svitlana O. Spasiteleva ◽  
Volodymyr L. Buriachok
Keyword(s):  
Large Data ◽  
Security Level ◽  
Successful Implementation ◽  
Development Platform ◽  
Blockchain Technology ◽  
Current State ◽  
New Models ◽  
Private And Public ◽  
Security Infrastructure ◽  
Definition Of

The article is devoted to the definition of problems using of blockchain technologies, and ways to overcome them to create distributed, secure applications. The paper considers the theoretical fundamentals of blockchain technologies and blockchain applications, new models of blockchain business, blockchain applications development platform, blockchain applications security, blockchain applications development problems, prospects for further research. The analysis of recent research and publications in the field of blockchain technologies are made in the article. Based on this analysis, it was determined that the blockchain industry has not yet completed the process of generating a generally accepted multilevel technology description. The overview of existing models of business blockchain, their characteristics and areas of application are done in the article. Software tools for creating and maintaining blockchain applications are considered. The article deals with the features, advantages and problems of using blockchain technology for creating distributed, secure applications. The problem of integration of new and existing private systems with an open blockchains is considered. A possible solution to this problem is the creation of a blockchain authentication service to implement a global security level. Such a service can become a standard security infrastructure for new models of mixed private and public systems that will be useful to all participants in different areas of the economy. The directions of development of protected blockchain applications in the sphere of public administration and private business in Ukraine are determined. In addition, the priority tasks that need to be solved for successful implementation of technology in Ukraine are determined based on the analysis of the current state of development of blockchains. There are three main areas of development of blockade technology: standardization, application security and integration of block systems with existing private systems and modern technologies of artificial intelligence, large data and the Internet of things, and described prospects for further research for them.

DIFFERENCE IN THE BEHAVIOR OF RIGHT-TURNING VEHICLES AND THEIR EFFECT ON SAFETY AT UNSIGNALIZED INTERSECTIONS IN MALAYSIA

2015 ◽  
Vol 76 (14) ◽  
Author(s):  
Ashar Ahmed ◽  
Ahmad Farhan Mohd Sadullah ◽  
Ahmad Shukri Yahya
Keyword(s):  
Descriptive Analysis ◽  
Stopping Rule ◽  
Road Vehicles ◽  
Unsignalized Intersections ◽  
Behavioral Observations ◽  
Minor Road ◽  
Stop Rule ◽  
Turning Maneuver ◽  
Larger Sample ◽  
Road Segments

Intersections are more prone to accidents as compared to straight road segments and vehicles that make right-turning maneuver are the ones which are more likely to be involved in an angle collision. Therefore, this study investigates their behavior at unsignalized intersections in Malaysia. The aim of this paper is to evaluate the compliance with the stop rule, use of turning indicator and right-turning behavior of minor road vehicles. All the behavioral observations were made with respect to two vehicle types which were ‘motorcycles’ and ‘others’. Descriptive analysis was presented and χ²-test was performed to investigate the association between the variables. It was found that most motorcyclists in Malaysia do not abide by the stopping rule at the intersection before making a right-turn. Moreover they seldom use their turning indicators and tend to make the indigenous ‘Weaving Merging Right-Turn’ (WMRT) more often as compared to other vehicles. Not complying with the stopping rule and keeping the indicator switched off while making a right-turn was found to be hazardous and resulted in the decrease in the safety of intersection and increase in the risk of accident. However, WMRT was found to be a safer maneuver as compared to the conventional right-turn. For vehicles other than motorcycles, the analysis concluded the same results. It is recommended that the methodology proposed in this research should be extended to other studies with a larger sample size. 

scholarly journals A New Model for Locating Plate Recognition Devices to Minimize the Impact of the Uncertain Knowledge of the Routes on Traffic Estimation Results

2020 ◽  
Vol 2020 ◽  
pp. 1-20 ◽  
Author(s):  
Santos Sánchez-Cambronero ◽  
Fernando Álvarez-Bazo ◽  
Ana Rivas ◽  
Inmaculada Gallego
Keyword(s):  
Traffic Management ◽  
Design Method ◽  
Traffic Network ◽  
Traffic Flows ◽  
Research Papers ◽  
Data Set ◽  
Essential Variable ◽  
Uncertain Knowledge ◽  
Definition Of ◽  
The Impact

A number of research papers have recently shown that the use of techniques based on the installation of vehicle identification devices allows us to address the observability problem of a traffic network in a much more efficient way than if it were done with traditional techniques. The use of such devices can lead to a better data set in terms of flows and therefore to a better definition of traffic flows, which is essential for traffic management in cities and regions. However, the current methodologies aimed at network modeling and data processing which are not fully adapted to the use of these devices in obtaining the necessary data for analyzing traffic and making network forecasts. This is because the essential variable in models which used data from plate scanning (as a particular case of AVI sensors) is composed of the route flows, while traditional methods are based on the observation of link and/or origin-destination flows. In this context, this paper proposes several practical contributions, in particular: (1) a traffic network design method aimed to use the plate scanning data to estimate traffic flows and (2) an algorithm for locating plate reader devices to reduce the effect of the uncertain knowledge of route enumeration. Next, using the well-known Nguyen-Dupuis network, a sensitivity analysis has been carried out to evaluate the influence of different parameters of the model on the final solution. These parameters are the considered routes, the degree of network simplification, and the available budget to install devices. Finally, the method has been applied to a real network.

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