scholarly journals Calculation of the Roadside Clear Zone Width along Highways Based on the Safe Slope

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Rui Cheng ◽  
Guozhu Cheng ◽  
Yulong Pei ◽  
Liang Xu
Keyword(s):  
Simulation Software ◽  
Practical Significance ◽  
Driving Safety ◽  
Horizontal Curve ◽  
Slope Gradient ◽  
Clear Zone ◽  
Zone Width ◽  
Interaction Detection ◽  
Vehicle Rollover ◽  
Curve Radius

International crash data indicate that roadside characteristics contribute to more than half of all roadside accidents involving serious injury or death. Therefore, research on roadside safety is urgently needed. Based on the vehicle departure speed, pavement height (i.e., the difference between pavement elevation and ground elevation), slope gradient, and horizontal curve radius, this study uses PC-Crash simulation software to carry out tests of trucks and cars exiting a road. A chi-squared automatic interaction detection (CHAID) decision tree is used to explore the causative mechanism of vehicle rollover, and the concept of a “safe slope” to ensure that vehicles do not roll over is proposed. Aiming at straight and curved sections, discriminant functions of vehicle rollover and nonrollover are fitted through Bayesian discriminant analysis, and safe slope calculation models for trucks and cars are then constructed. Based on the obtained safe slope models, calculation methods for the safe slope and the roadside clear zone width involving different traffic compositions are proposed by calibrating the lateral distance from the final position of nonrollover vehicles to the road edge. The results show that the factors affecting vehicle rollover are, in descending order of importance, the slope gradient, pavement height, vehicle type, departure speed, and horizontal curve radius. For a section with a large proportion of cars, the slope gradient should not be steeper than 1:3.5. The horizontal curve radius should not be less than 600 m for a section with a large proportion of trucks and a slope gradient steeper than 1:3.5 or shallower than 1:2.5. Additionally, for a section with a pavement higher than 0.5 m and a slope gradient steeper than 1:2.5, the operating speed limit should be lower than 60 km/h. These research results have theoretical value and practical significance to improve the driving safety level and reducing the risk of roadside accidents.

scholarly journals A Design Method for the Roadside Clear Zone Based on Accident Simulation Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Rui Cheng ◽  
Ye Pan ◽  
Tao Wang
Keyword(s):  
Simulation Analysis ◽  
Design Method ◽  
Risk Index ◽  
Cost Benefit ◽  
Horizontal Curve ◽  
Clear Zone ◽  
Index Method ◽  
Cost Benefit Ratio ◽  
Accident Simulation ◽  
Curve Radius

In order to improve the safety design of roadside areas and reduce the loss of roadside accidents, this paper uses PC-Crash software to perform an accident simulation analysis. By recording the track of the vehicle after entering the roadside, the recommended widths of the roadside clear zone for different operating speeds and horizontal curve radii in straight and curved sections are given. According to our previous research data, the conditions for setting the roadside clear zone are proposed. Finally, based on a cost-benefit ratio analysis, a comprehensive risk index method is adopted to evaluate the social stability risk of the project and conduct research on the design method of the roadside clear zone. The results show that the width of the roadside clear zone has an exponential relation with the departure speed and a power relation with the horizontal curve radius. The research results realize the accurate calculation of the roadside clear zone width and fill in the gaps of the relevant specifications and guidelines in the setting conditions of the roadside clear zone.

scholarly journals Probability of Roadside Accidents for Curved Sections on Highways

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Guozhu Cheng ◽  
Rui Cheng ◽  
Yulong Pei ◽  
Liang Xu
Keyword(s):  
Risk Factors ◽  
Decision Rules ◽  
Significant Risk ◽  
Vehicle Speed ◽  
Probabilistic Prediction ◽  
Interaction Detection ◽  
Probability Prediction ◽  
Chi Squared ◽  
Longitudinal Slope ◽  
Curve Radius

To predict the probability of roadside accidents for curved sections on highways, we chose eight risk factors that may contribute to the probability of roadside accidents to conduct simulation tests and collected a total of 12,800 data obtained from the PC-crash software. The chi-squared automatic interaction detection (CHAID) decision tree technique was employed to identify significant risk factors and explore the influence of different combinations of significant risk factors on roadside accidents according to the generated decision rules, so as to propose specific improved countermeasures as the reference for the revision of the Design Specification for Highway Alignment (JTG D20-2017) of China. Considering the effects of related interactions among different risk factors on roadside accidents, path analysis was applied to investigate the importance of the significant risk factors. The results showed that the significant risk factors were in decreasing order of importance, vehicle speed, horizontal curve radius, vehicle type, adhesion coefficient, hard shoulder width, and longitudinal slope. The first five important factors were chosen as predictors of the probability of roadside accidents in the Bayesian network analysis to establish the probability prediction model of roadside accidents. Eventually, the thresholds of the various factors for roadside accident blackspot identification were given according to probabilistic prediction results.

Analysis on the Anti-Glare Plate Setting Distance on Horizontal Curve Sections of Expressway

2014 ◽  
Vol 587-589 ◽  
pp. 2156-2159 ◽  
Author(s):  
Tian Xiao ◽  
Ji Shu Sun ◽  
Can Zhang Jin
Keyword(s):  
Traffic Safety ◽  
Calculation Formula ◽  
Horizontal Curve ◽  
Distance Calculation ◽  
Element Simulation ◽  
Curved Section ◽  
Curve Radius ◽  
The Relationship ◽  
Plate Distance ◽  
Glare Effect

Glare is one of the most important factors threating expressway traffic safety an night. The most commonly way to prevent glaring night is to set anti-glare plate. Different from the straight sections of expressway, the relationship between the front light of vehicles and the distance of anti-glare plate on the horizontal curved section has some-what changed. Through a lot of tests and finite element simulation, the relationship between the distance of anti-glare plate, horizontal curve radius and anti-glare effect were analyzed systematically. Distance calculation formula of anti-glare plate in horizontal curve sections was revised in this paper. The anti-glare plate distance requirement under different expressway alignment design indexes and its calculation formula was proposed. The achievement was beneficial to confirm the anti-glare effect and improve traffic safety. It can provide us with a reference and a supplement of the specification.

An Evaluation of Highway Work Zone Impact Factors on Driving Safety Using Complicated Indexes Based on Traffic Simulation System

2013 ◽  
Vol 723 ◽  
pp. 943-950 ◽  
Author(s):  
Jiao Yan ◽  
Chi Zhang ◽  
Meng Hua Ding ◽  
Yi Chang James Tsai
Keyword(s):  
Traffic Control ◽  
Traffic Simulation ◽  
Compliance Rate ◽  
Simulation Software ◽  
Work Zone ◽  
Driving Safety ◽  
Impact Factors ◽  
Speed Limit ◽  
Transition Area ◽  
Control And Management

There are quite a number of complicated factors that can affect driving safety on freeway work zone during reconstruction, for example, traffic volume, driver compliance rate (which means drivers who follow the posted speed limit), slope gradient, HGV rate and so on. This article uses the popular traffic simulation software VISSIM to simulate different situations. The results show that the safety of Upstream Transition Area and the place where speed limit signs locate are the lowest. It is recommended that speed limit signs should not be located that much, and cars and HGVs need to be more careful when merging into the Upstream Transition Area, and lower their speeds if necessary. Most important, compliance rate plays an important role in safety measures, and this provides a solid foundation for traffic control and management.

Simulation and Analysis for New Contact System of Control and Protective Switching Based on Ansoft Maxwell

2012 ◽  
Vol 229-231 ◽  
pp. 1963-1966
Author(s):  
Zhi Yuan Cai ◽  
Zhan Nan Guo
Keyword(s):  
Low Voltage ◽  
Simulation Software ◽  
Contact System ◽  
Field Analysis ◽  
Practical Significance ◽  
Electromagnetic Simulation ◽  
Circuit Breakers ◽  
Magnetic Field Analysis ◽  
Overall Performance ◽  
Breaking Time

CPS (control and protective switching) one of the smart integrated include the function of circuit breakers, contactors, and low-voltage electrical appliances. The contact system is different from the traditional low-voltage electrical function. Well-designed structure of the contact system has important practical significance for overall performance of CPS. The paper proposes a new contact system. The simulation analyze the electrical repulsion of the traditional contact system and a new contact system under different current size, breaking time, blowing arc magnetic field analysis by electromagnetic simulation software. According to the results of the simulation comparison, prove that the new contactor structure making the function of CPS increased.

scholarly journals Collision prediction on combined horizontal and vertical alignments of two-lane rural highways.

2021 ◽  
Author(s):  
Qing Chong You
Keyword(s):  
Associated Factors ◽  
Negative Binomial ◽  
Horizontal Curve ◽  
Rural Highways ◽  
Vehicle Accidents ◽  
Horizontal Curves ◽  
Curve Radius ◽  
Grade Increase ◽  
Minimum Ratio ◽  
Successful Predictor

This study investigates the safety effects of combined horizontal and vertical alignments using accident occurrences on two-lane rural highways in Washington. Eight statistical models were developed to establish the relationships between vehicle accidents and their associated factors for eight combinations of alignments by the Poisson, negative binomial, zero-inflated Poisson, and zero-inflated negative binomial. Three selected models were validated. The findings show that degree of curvature is the most successful predictor for horizontal curves combined with vertical alignments. A minimum ratio of 25 of vertical curve radius to horizontal curve radius is recommended for a curve with radius of smaller than 6000 ft (or 1830 m). Vertical curves have relatively little influence on accident occurrences at horizontal tangents. The grade value and length of a grade increase accident occurrences when a horizontal curve or tangent is on a grade. A smaller curve should be avoided introducing at a steep grade.

scholarly journals Collision prediction on combined horizontal and vertical alignments of two-lane rural highways.

2021 ◽  
Author(s):  
Qing Chong You
Keyword(s):  
Associated Factors ◽  
Negative Binomial ◽  
Horizontal Curve ◽  
Rural Highways ◽  
Vehicle Accidents ◽  
Horizontal Curves ◽  
Curve Radius ◽  
Grade Increase ◽  
Minimum Ratio ◽  
Successful Predictor

This study investigates the safety effects of combined horizontal and vertical alignments using accident occurrences on two-lane rural highways in Washington. Eight statistical models were developed to establish the relationships between vehicle accidents and their associated factors for eight combinations of alignments by the Poisson, negative binomial, zero-inflated Poisson, and zero-inflated negative binomial. Three selected models were validated. The findings show that degree of curvature is the most successful predictor for horizontal curves combined with vertical alignments. A minimum ratio of 25 of vertical curve radius to horizontal curve radius is recommended for a curve with radius of smaller than 6000 ft (or 1830 m). Vertical curves have relatively little influence on accident occurrences at horizontal tangents. The grade value and length of a grade increase accident occurrences when a horizontal curve or tangent is on a grade. A smaller curve should be avoided introducing at a steep grade.

scholarly journals Investigating Automobile Passengers’ Comfort and Safety on Scenic Road Using Sideway Force Coefficient

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ronghua Wang ◽  
Xingliang Liu ◽  
Feijie Han
Keyword(s):  
Numerical Simulation ◽  
Large Scale ◽  
Lateral Acceleration ◽  
Driving Safety ◽  
Horizontal Curve ◽  
Force Coefficient ◽  
Safe Driving ◽  
Minimum Radius ◽  
Curve Design ◽  
Naturalistic Driving

To satisfy passengers’ experiential demand in scenic roads, a study on passengers’ comfort in the aspect of horizontal curve design is stated in this study. A new indicator sideway force coefficient (SFC) describing passengers’ comfort is introduced, which differs from lateral acceleration. The mechanism of SFC is provided depending on the dynamic balance condition of the vehicle on horizontal curve and S F C c representing passengers’ comfort tolerance limitation is investigated. A large scale naturalistic driving experiments along a park road are conducted, and the S F C c value from naturalistic driving experiments is verified through numerical simulation of 15 horizontal curves from 5 scenic roads from the perspectives of both passengers’ comfort and driving safety. The statistical analysis on data collected in field tests indicates that age and gender have no effect on S F C c , and the value of S F C c is determined as 0.291. The corresponding minimum radius limits under 20–60 km/h and superelevation 6%, 8%, and 10% are proposed. The numerical simulation denotes, when satisfying the comfort demand of passengers (SFC less than 0.291), the lateral distance path is in a safe range, which could also satisfy the safe driving requirements. Thus, S F C c and minimum radius limits proposed in this study are proved to be credible and appropriate for the curve design of horizontal alignment in scenic roads.

Experimental analysis and 1D simulation of an advanced hybrid boosting system for automotive applications in transient operation

2021 ◽  
pp. 146808742110601
Author(s):  
Silvia Marelli ◽  
Vittorio Usai
Keyword(s):  
Steady State ◽  
Transient Response ◽  
Simulation Software ◽  
Pollutant Emissions ◽  
Practical Significance ◽  
Steady State Condition ◽  
Automotive Engines ◽  
Electrically Assisted ◽  
Turbocharging System ◽  
The University

Due to the increasingly restrictive limits of pollutant emissions, electrification of automotive engines is now mandatory. For this reason, adopting hybrid boosting systems to improve brake specific fuel consumption and time-to-boost is becoming common practice. In this paper an advanced turbocharging system is analyzed, consisting in an electrically assisted radial compressor and a traditional turbocharger. As a first step, the steady-state performance of each component was measured at the University of Genoa test rig. Subsequently another experimental campaign was carried out to evaluate the transient response of the entire turbocharging system. Two different layouts were compared: upstream and downstream. In the upstream configuration the electrically assisted compressor was placed in front of the traditional turbocharger, in the downstream configuration the e-compressor was positioned after the traditional turbocharger. The two different coupling configurations, upstream and downstream, were then modeled in 1-D simulation software following the dimensions and characteristics of the experimental line from which the exploited data originates. The models were first validated by emulating the steady-state condition and subsequently the transient response was simulated and analyzed. Secondly, the transient response of the two layouts was compared, removing the constraints imposed by the experimental activity. The practical significance of the results is outlined, with reference to the transient response of the turbocharger. The adoption of the boosting system presented here allows a fast and stable transient response. Moreover, a reduction in the engine back pressure could be achieved through an optimization of the boosting system-engine matching calculation.

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