Empirical Analysis on Time to Collision at Urban Expressway

2014 ◽  
Vol 505-506 ◽  
pp. 1127-1132 ◽  
Author(s):  
Cheng Xu ◽  
Zhao Wei Qu
Keyword(s):  
Empirical Analysis ◽  
Traffic Safety ◽  
Traffic Volume ◽  
T Test ◽  
Descriptive Statistics ◽  
Traffic Condition ◽  
Time To Collision ◽  
Traffic Conditions ◽  
Urban Expressway ◽  
Traffic Conflicts

Traffic safety is of great significance, especially at urban expressway where traffic volume is large and traffic conflicts are highlighted. But little research up to date has discussed in detail how these factors impact the TTC characteristics. In this paper, field Beijing expressway data were collected by video with different locations, lanes, traffic conditions and following vehicle types. Accordingly, some basic descriptive statistics of total TTC samples were shown and analyzed. We then used T-test to analyze the effect of road environments, traffic conditions, and vehicle types on TTC statistically. The results implied three main findings. Firstly, TTC was found to change according to road environments (i.e. TTC on weaving segment is smaller than other locations), secondly, some evidence supported this hypothesis that traffic conditions (especially uncongested traffic condition) affect TTC significantly, and lastly, little correlation was found between TTC means and vehicle types.

scholarly journals Exploring the Influence of Truck Proportion on Freeway Traffic Safety Using Adaptive Network-Based Fuzzy Inference System

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Shiwen Zhang ◽  
Yingying Xing ◽  
Jian Lu ◽  
H. Michael Zhang
Keyword(s):  
Traffic Safety ◽  
Fuzzy Inference System ◽  
Fuzzy Inference ◽  
Traffic Volume ◽  
Learning Ability ◽  
Adaptive Network ◽  
Freeway Traffic ◽  
Inference System ◽  
Traffic Conflicts ◽  
The Impact

The truck operation of freeway has an impact on traffic safety. In particular, the gradually increasing in truck proportion will inevitably affect the freeway traffic operation of different traffic volume. In this paper, VISSIM simulation is used to supply the field data and orthogonal experimental is designed for calibrate the simulation data. Then, SSAM modeling is combined to analyze the impact of truck proportion on traffic flow parameters and traffic conflicts. The serious and general conflict prediction model based on the Adaptive Network-based Fuzzy Inference System (ANFIS) is proposed to determine the impact of the truck proportion on freeway traffic safety. The results show that when the truck proportion is around 0.4 under 3200 veh/h and 0.6 under 2600 veh/h, there are more traffic conflicts and the number of serious conflicts is more than the number of general conflicts, which also reflect the relationship between truck proportion and traffic safety. Under 3000 veh/h, travel time and average delay increasing while mean speed and mean speed of small car decreases with truck proportion increases. The mean time headway rises largely with the truck proportion increasing above 3000 veh/h. The speed standard deviation increases initially and then fall with truck proportion increasing. The lane-changing decreases while truck proportion increasing. In addition, ANFIS can accurately determine the impact of truck proportion on traffic conflicts under different traffic volume, and also validate the learning ability of ANFIS.

scholarly journals Comprehensive Operation Risk Assessment of a Highway Maintenance Area Based on Reliability

2021 ◽  
Vol 13 (16) ◽  
pp. 8744
Author(s):  
Nan Ouyang
Keyword(s):  
Traffic Safety ◽  
Traffic Volume ◽  
Speed Limit ◽  
Regression Equations ◽  
Limit Values ◽  
Activity Area ◽  
Traffic Conflicts ◽  
Traffic Volumes ◽  
Operation Risk ◽  
Traffic Organization

To study the influence of various working conditions on traffic safety in the maintenance area of a mountain expressway, 675 groups of PTV VISSIM traffic simulation experiments were designed with various traffic organization modes, traffic volumes, traffic compositions, activity area lengths, and speed limit values. The results show that the activity area length of a closed lane, a compressed lane, and a borrowed opposite lane had no marked influence on the traffic conflicts. There was a significant positive correlation between the proportion of trucks and the number of traffic conflicts, and the number of traffic conflicts increased significantly with an increase in traffic volume. In the closed lane and borrowed opposite lane scenarios, the increase in traffic conflicts was more obvious with the increase in traffic volume. There were obvious differences in the number of traffic conflicts under different forms of traffic organization. The number of conflicts in the compressed lane scenario was the lowest, and in the borrowed opposite lane scenario the number of conflicts was the highest. There was a significant correlation between a decrease in the speed limit and an increase in the number of traffic conflicts. Finally, with traffic volume, truck proportion, and speed limit values as independent variables and reliability as a dependent variable, linear regression equations of reliability were established for three traffic organization scenarios: closed lane, borrowed opposite lane, and compressed lane.

scholarly journals Study of Traffic Volume and its Safety Measurement at Dadabari Circle, Career Point University, Kota

2018 ◽  
Vol 8 (01) ◽  
Author(s):  
Raj Pratap Singh ◽  
Himanshu Tekwani ◽  
Bhavesh Joshi ◽  
Pratheek Sudhakaran ◽  
Jitendra Singh
Keyword(s):  
Traffic Flow ◽  
Traffic Safety ◽  
Traffic Volume ◽  
Heterogeneous Traffic ◽  
Traffic Condition ◽  
Passenger Car ◽  
The Road ◽  
Traffic Lane ◽  
Wide Range ◽  
On The Road

The knowledge of traffic volume is an important basic input required for planning, analysis and operation of roadway systems. A significant effort has been made in order to study the Traffic Volume of Dadabari Chauraha. For better understanding of the present status of traffic flow at the junction, traffic survey is conducted. The safe and time efficient movement of the people and goods is dependent on Traffic flow, which is directly connected to the traffic characteristics. In Traffic Flow we have to consider generally three parameters, Volume, Speed, and Capacity. While as a traffic volume may be defined as the number of vehicles passing a given section of road or traffic lane per unit time will be inappropriate when several types of vehicles with widely varying static and dynamic characteristics are comprised in the traffic. Due to mixed nature of traffic it gets difficult to accommodate all the kinds of traffic on these roads. The basic problem arises during the peak hours of the day when the traffic volume is highest on the road. The interaction between moving vehicles under such heterogeneous traffic condition is highly complex. The problem of measuring volume of such kind of traffic has been addressed by converting the different types of vehicles into equivalent passenger cars and expressing the volume in terms of Passenger Car Unit (PCU) per hour. Calculation of Passenger Car Units (PCU’s) for different vehicle types had been made. For a wide range of traffic volume and roadway conditions indicate that the PCU value of a vehicle significantly changes with change in traffic volume and width of roadway. some of the remedial measures to improve the traffic safety in the region such as widening the road, changing 4-lane to 6-lane or by providing more public transport can be recommended based on the outcomes of the work.

Study on Traffic Flow Parameters Model of Expressway Interchanges Opening Distance

2012 ◽  
Vol 178-181 ◽  
pp. 2623-2628
Author(s):  
Wei Liu ◽  
Xia Chen ◽  
Ayong Hu
Keyword(s):  
Traffic Management ◽  
Minimum Distance ◽  
Road Traffic ◽  
Traffic Volume ◽  
Traffic Conditions ◽  
Flow Parameters ◽  
Urban Expressway ◽  
Combination Modes ◽  
The Relationship

The operational safety and service quality of urban expressway are greatly affected by the distance of interchange opening. This paper definited the distance of 4 kinds of opening combination modes, showed the calculation models, and established a piecewise function model of opening distance, traffic volume and speed. It also proposed that, meeting the requirements of minimum distance, the opening distance should be determined with the consideration of actual road traffic conditions, by analyzing the relationship between the opening distance, traffic volume and speed. The results can be the references for the traffic management and the planning and designing of urban expressway interchange.

scholarly journals A New Traffic Conflict Measure for Electric Bicycles at Intersections

2020 ◽  
Vol 32 (3) ◽  
pp. 309-320
Author(s):  
Zhizhou Wu ◽  
Xin Zeng ◽  
Ling Wang
Keyword(s):  
Traffic Safety ◽  
Video Recording ◽  
Time To Collision ◽  
Safety Improvement ◽  
Traffic Conflicts ◽  
Traffic Conflict ◽  
Relative Kinetic ◽  
Electric Bicycles ◽  
Conflict Risk ◽  
High Flexibility

As electric bicycles (e-bikes) are becoming popular in China, concerns have been raised about their safety conditions. A traffic conflict technique is commonly used in traffic safety analysis, and there are many conflict measures designed for cars. However, e-bikes have high flexibility to change speed and trajectories, which is different from cars, so the conflict measures defined for e-bikes need to be independently explored. Based on e-bike driving characteristics, this paper proposes a new measure, the Integrated Conflict Intensity (ICI), for traffic conflicts involving e-bikes at intersections. It measures the degree of dangerousness of a conflict process, with consideration of both conflict risk and conflict severity. Time to collision is used to measure the conflict risk. Relative kinetic energy is used to measure the conflict severity. ICI can be calculated based on video analysis. The method of determining ICI thresholds for three conflict levels (serious, less serious, and slight) and two conflict types (conflicts between two e-bikes, and conflicts between an e-bike and a car) is put forward based on the questionnaires about safety perception of e-bike riders, which is regarded as the criterion of e-bike safety conditions at intersections. The video recording and a questionnaire survey about conflicts involving e-bikes at intersections have been conducted, and the unified thresholds applicable to different intersections have been determined. It is verified that ICI and its thresholds meet the criterion of e-bike safety conditions. This work is expected to be used in the selection of intersections for safety improvement of e-bike traffic.

scholarly journals Traffic Risk Modelling and Analysis under Airport-Like Simulation Environment

2022 ◽  
Vol 2022 ◽  
pp. 1-10
Author(s):  
Yanting Sheng ◽  
Rui Feng ◽  
Salvatore Antonio Biancardo
Keyword(s):  
Traffic Safety ◽  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Vehicle Safety ◽  
Collision Risk ◽  
Risk Modelling ◽  
Time To Collision ◽  
Additional Information ◽  
Traffic Conditions ◽  
Research Findings

Traffic safety plays a crucial role in the development of autonomous vehicles which attracts significant attention in the community. It is a challenge task to ensure autonomous vehicle safety under varied traffic environment interference, especially for airport-like closed-loop conditions. To that aim, we analyze autonomous vehicle safety at typical roadway conditions and traffic state constraints (e.g., car-following state at different speed distributions) by simulating the airport-like traffic conditions. The experimental results suggest that traffic collision risk is in a positive relationship with the speed difference and distance among adjacent vehicles. More specifically, the autonomous vehicle may collide with neighbors when the time to collision (TTC) indicator is lower than 4 s, and vice versa. The research findings can help both research community and practioners obtain additional information for improving traffic safety for autonomous vehicles.

Pregnant women readiness to use the Internet to access health information about pregnancy and childbirth: A cross-sectional study (Preprint)

2019 ◽  
Author(s):  
Leila Ahmadian ◽  
Reza Khajouei ◽  
Sudabeh Kamali ◽  
Moghaddameh Mirzaee ◽  
Arefeh Ameri
Keyword(s):  
Pregnant Women ◽  
Health Information ◽  
Demographic Characteristics ◽  
T Test ◽  
Descriptive Statistics ◽  
The Internet ◽  
Chi Square ◽  
Readiness Assessment ◽  
Pregnancy And Childbirth ◽  
Chi Square Test

BACKGROUND Today, the Internet may be a promising tool for interventions for pregnant women. However, these kinds of tools are only helpful if users are ready to use them. OBJECTIVE The present study was conducted with the aim of readiness assessment of pregnant women to use the Internet to access health information about pregnancy and childbirth. METHODS This study was carried out on a sample of 384 pregnant women. Data were collected using a valid and reliable questionnaire. The first section of this questionnaire collected demographic characteristics of the participants. The second part of the questionnaire contains 27 questions covering the following components: infrastructure readiness (6 questions); affordability readiness (3 questions); and skill readiness (12 questions). Data were analyzed with SPSS 19.0 using descriptive statistics, Chi-square test, and T-test. RESULTS This study was carried out on a sample of 384 pregnant women. Data were collected using a valid and reliable questionnaire. The first section of this questionnaire collected demographic characteristics of the participants. The second part of the questionnaire contains 27 questions covering the following components: infrastructure readiness (6 questions); affordability readiness (3 questions); and skill readiness (12 questions). Data were analyzed with SPSS 19.0 using descriptive statistics, Chi-square test, and T-test. CONCLUSIONS The use of the Internet by pregnant women depends on factors such as infrastructure, affordability, and skills readiness. This study showed that speed and the quality of the Internet, hardware and software availability, affordability of the Internet, and access to the Internet training were factors in measuring E-health readiness assessment. CLINICALTRIAL Not applicable

scholarly journals COVID Lockdowns, Social Distancing, and Fatal Car Crashes: More Deaths on Hobbesian Highways?

2020 ◽  
Vol 4 (3-4) ◽  
pp. 238-259 ◽  
Author(s):  
Marshall W. Meyer
Keyword(s):  
World War Ii ◽  
Traffic Safety ◽  
Motor Vehicle ◽  
Road Traffic ◽  
Research Question ◽  
Traffic Volume ◽  
Similar Data ◽  
World War ◽  
Social Distancing ◽  
The Usa

Abstract Research Question What happened to US traffic safety during the first US COVID-19 lockdown, and why was the pattern the opposite of that observed in previous sudden declines of traffic volume? Data National and local statistics on US traffic volume, traffic fatalities, injury accidents, speeding violations, running of stop signs, and other indicators of vehicular driving behavior, both in 2020 and in previous US economic recessions affecting the volume of road traffic. Methods Comparative analysis of the similarities and differences between the data for the COVID-19 lockdown in parts of the USA in March 2020 and similar data for the 2008–2009 global economic crisis, as well as other US cases of major reductions in traffic volume. Findings The volume of traffic contracted sharply once a COVID-19 national emergency was declared and most states issued stay-at-home orders, but motor vehicle fatality rates, injury accidents, and speeding violations went up, and remained elevated even as traffic began returning toward normal. This pattern does not fit post-World War II recessions where fatality rates declined with the volume of traffic nor does the 2020 pattern match the pattern during World War II when traffic dropped substantially with little change in motor vehicle fatality rates. Conclusions The findings are consistent with a theory of social distancing on highways undermining compliance with social norms, a social cost of COVID which, if not corrected, poses potential long-term increases in non-compliance and dangerous driving.

Using Traffic Disturbance Metrics to Estimate and Predict Freeway Traffic Breakdown and Safety Events

2021 ◽  
pp. 036119812110124
Author(s):  
Leila Azizi ◽  
Mohammed Hadi
Keyword(s):  
Traffic Safety ◽  
Management Strategies ◽  
Connected Vehicles ◽  
Freeway Traffic ◽  
Transportation Management ◽  
Time To Collision ◽  
Decision Tools ◽  
Traffic State ◽  
Traffic Performance ◽  
Traffic Disturbance

The introduction of connected vehicles, connected and automated vehicles, and advanced infrastructure sensors will allow the collection of microscopic metrics that can be used for better estimation and prediction of traffic performance. This study examines the use of disturbance metrics in combination with the macroscopic metrics usually used for the estimation of traffic safety and mobility. The disturbance metrics used are the number of oscillations and a measure of disturbance durations in the time exposed time to collision. The study investigates using the disturbance metrics in data clustering for better off-line categorization of traffic states. In addition, the study uses machine-learning based classifiers for the recognition and prediction of the traffic state and safety in real-time operations. The study also demonstrates that the disturbance metrics investigated are significantly related to crashes. Thus, this study recommends the use of these metrics as part of decision tools that support the activation of transportation management strategies to reduce the probability of traffic breakdown, ease traffic disturbances, and reduce the probability of crashes.

scholarly journals Energy and Environmental Implications of Using Energy-Harvesting Speed Humps in Nablus City, Palestine

Atmosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 937
Author(s):  
Fady M. A. Hassouna ◽  
Mahmoud Assad ◽  
Islam Koa ◽  
Wesam Rabaya ◽  
Aya Aqhash ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Ghg Emissions ◽  
Traffic Volume ◽  
Environmental Implications ◽  
Traffic Conditions ◽  
National University ◽  
Energy Consuming ◽  
The Cost ◽  
Annual Amount ◽  
Speed Humps

Over the last three decades, transportation has become one of the main energy-consuming sectors around the world and, as a result, large amounts of emissions are produced, contributing to global warming, climate change, and health problems. Therefore, huge investments and efforts have been made by governments and international institutions to find new renewable and clean sources of energy. As a contribution to these efforts, this study determined the practical energy and environmental implications of replacing conventional speed humps with energy-harvesting speed humps in Nablus city, Palestine. The study was implemented using an energy-harvesting speed hump (EHSH) system developed in the laboratories at An-Najah National University and based on comprehensive traffic volume counts at all speed humps’ locations. In addition, a traffic volume prediction model was developed in order to determine the implications over the next 10 years. As a result of the study, the expected annual amount of generated energy was determined. Moreover, the expected reduction in greenhouse gas (GHG) emissions and the reduction in the cost of roadway network lighting were determined based on the current and future traffic conditions.

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