scholarly journals Three-Dimensional Stopping Sight Distance Calculation Method under High Slope Restraint

2020 ◽  
Vol 10 (20) ◽  
pp. 7118
Author(s):  
Yonghong Yang ◽  
Jiecong Wang ◽  
Yuanbo Xia ◽  
Lan Huang
Keyword(s):  
Calculation Method ◽  
Three Dimensional ◽  
Highway Safety ◽  
Small Radius ◽  
Safety Engineering ◽  
Design Data ◽  
Important Indicator ◽  
High Slope ◽  
Sight Distance ◽  
Stopping Sight Distance

Sight distance is an important indicator to ensure the safety of drivers, and is also an indispensable evaluation basis in highway safety engineering. In mountainous highways, high slopes and small radius often lead to poor visibility and traffic accidents. Through the combined calculation of horizontal and vertical sections, this paper comprehensively considers the specific sizes of roadside clearance, high slope, as well as the position and height of the driver’s view point and other factors, and it analyzes the limited visibility of the driver in the process of driving right turn. An effective and simplified calculation method based on design data for three dimensional (3D) stopping sight distance (S.S.D.) in high fill sections is proposed. Finally, the S.S.D. inspection of the actual highway, based on design speed and operating speed, is carried out, and the sight distance of the calculated point is judged by comparing the value with the normal value and the calculation result of the horizontal sightline offset. The results show that the method proposed in this paper is consistent with the sight distance results obtained by the horizontal sightline offset method, which indicates the calculation method is accurate and provides a technical reference for S.S.D. evaluation in highway safety engineering.

Sight distance red zones on combined horizontal and sag vertical curves

1998 ◽  
Vol 25 (4) ◽  
pp. 621-630 ◽  
Author(s):  
Yasser Hassan ◽  
Said M Easa
Keyword(s):  
Quantitative Analysis ◽  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Horizontal Curve ◽  
Sight Distance ◽  
Stopping Sight Distance ◽  
Three Dimensional Models ◽  
Highway Alignment ◽  
Current Standards

Coordination of highway horizontal and vertical alignments is based on subjective guidelines in current standards. This paper presents a quantitative analysis of coordinating horizontal and sag vertical curves that are designed using two-dimensional standards. The locations where a horizontal curve should not be positioned relative to a sag vertical curve (called red zones) are identified. In the red zone, the available sight distance (computed using three-dimensional models) is less than the required sight distance. Two types of red zones, based on stopping sight distance (SSD) and preview sight distance (PVSD), are examined. The SSD red zone corresponds to the locations where an overlap between a horizontal curve and a sag vertical curve should be avoided because the three-dimensional sight distance will be less than the required SSD. The PVSD red zone corresponds to the locations where a horizontal curve should not start because drivers will not be able to perceive it and safely react to it. The SSD red zones exist for practical highway alignment parameters, and therefore designers should check the alignments for potential SSD red zones. The range of SSD red zones was found to depend on the different alignment parameters, especially the superelevation rate. On the other hand, the results showed that the PVSD red zones exist only for large values of the required PVSD, and therefore this type of red zones is not critical. This paper should be of particular interest to the highway designers and professionals concerned with highway safety.Key words: sight distance, red zone, combined alignment.

scholarly journals Three-dimensional stopping sight distance control on passing lanes of divided highways

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
Stergios Mavromatis ◽  
Fotis Mertzanis ◽  
Giorgos Kleioutis ◽  
Basil Psarianos
Keyword(s):  
Three Dimensional ◽  
Distance Control ◽  
Sight Distance ◽  
Stopping Sight Distance

Three-Dimensional, Probabilistic Highway Design

2008 ◽  
Vol 2060 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Mohamed Sarhan ◽  
Yasser Hassan
Keyword(s):  
Reliability Analysis ◽  
Probabilistic Approach ◽  
Three Dimensional ◽  
Design Parameters ◽  
Horizontal Curve ◽  
Vertical Alignment ◽  
Highway Design ◽  
Side Slope ◽  
Sight Distance ◽  
Stopping Sight Distance

The potential usefulness of reliability analysis has recently been stressed in many engineering applications. Given the variability in the design parameters, a reliability-based probabilistic approach is well suited to replace the current deterministic highway design practice. However, progress in this regard is generally slow. In this study, the reliability analysis was used to estimate the probability of hazard (POH) that might result from insufficiency of sight distances. As an application, the available sight distance was checked against required stopping sight distance on an assumed road segment. Variation of the design parameters was addressed with Monte Carlo simulation using 100,000 sets of design parameters based on distributions available in the literature. A computer program was developed to use these sets of design parameters to calculate the profiles of available and required stopping sight distances in two- and three-dimensional projections as well as the profile of POH. The approach was applied to a horizontal curve overlapping with flat grade, crest curves, and sag curves in a cut section where the side slope would restrict the sightline. The analysis showed that the current deterministic approach yields very conservative estimates of available and required stopping sight distance, resulting in very low POH. The application example also showed the change of POH with the change of vertical alignment parameters.

Calculation method of belt material parameters for finite element tire model

2021 ◽  
pp. 095440702110422
Author(s):  
Lu Zhang ◽  
Shaohua Wang ◽  
Bing Li
Keyword(s):  
Finite Element ◽  
Calculation Method ◽  
Complex Structure ◽  
Three Dimensional ◽  
Anisotropic Elasticity ◽  
Dynamic Responses ◽  
Reinforced Composites ◽  
Tire Model ◽  
Material Parameters ◽  
Vehicle Dynamic Simulation

The radial tire belt is composed of multi-layered fiber-reinforced cords with a very complex structure. Restricted by the computing speed, the simplified finite element (FE) tire model with equivalent belt is usually applied in the vehicle dynamic simulation. However, it is always difficult to obtain the material parameters of the equivalent belt. In this paper, a calculation method of equivalent belt material parameters for the simplified FE tire model is proposed based on the three-dimensional (3-D) anisotropic elasticity of the cord reinforced composites. The simulation results of the static radial stiffness, modal characteristics, and dynamic responses for the simplified FE tire model with parameters obtained by the calculation method were compared with experiment results. The results show that the deviation between the experiment and simulation is acceptable, and the validity of the calculation method is verified.

Local Natural Ventilation Registration while Ensuring Aerological Safety at the Mining Enterprises

2021 ◽  
pp. 60-65
Author(s):  
S.S. Kobylkin ◽  
◽  
V.M. Khubieva ◽  
Keyword(s):  
Calculation Method ◽  
Natural Ventilation ◽  
Three Dimensional ◽  
Field Measurements ◽  
Industrial Safety ◽  
Ventilation Network ◽  
Negative Consequences ◽  
Practical Application ◽  
Mining Operations ◽  
Mine Workings

Safety of mining operations is the basis for the efficient functioning of the mines. During mining operations, due to changing conditions in the mine workings, the natural draft began to appear more frequent. Moreover, its influence can be limited to a separate section without affecting the entire ventilation network. In this paper, the new concept is introduced and explained — local natural ventilation. The classification signs and the negative consequences of its manifestation are presented. Main difference between the local natural ventilation as a subspecies of natural ventilation as a whole lies in the limited action both in the spaces of mine workings or individual sections, and in time. Particularly its occurrence depends on the season or the technological processes performed. In this case, the local natural ventilation is not an emergency and is not subject to registration as an incident or accident. However, its manifestations can lead to both incidents and accidents. Taking this factor into account will allow to increase the level of aerological safety at the mining enterprises. A method of three-dimensional computer modeling is proposed for predicting the manifestation of local natural ventilation and making decisions to prevent it. An example of the use of this approach at the Norilsk mine during the construction of shafts with verification of field measurements is given. It confirms the possibility of practical application of the proposed calculation method. The algorithm for registering the local natural ventilation considered in the article makes it possible to develop activities for improving the level of industrial safety at the mining enterprises as a whole.

Calculation Method of Three-dimensional Attitude Angle Based on Atmospheric Polarization Pattern

2020 ◽  
Vol 57 (22) ◽  
pp. 221107
Author(s):  
杨江涛 Yang Jiangtao ◽  
王健安 Wang Jian''an ◽  
王银 Wang Yin ◽  
胡啸 Hu Xiao
Keyword(s):  
Calculation Method ◽  
Three Dimensional ◽  
Polarization Pattern ◽  
Attitude Angle

scholarly journals An Initial Investigation of the Effects of a Fully Automated Vehicle Fleet on Geometric Design

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
John Khoury ◽  
Kamar Amine ◽  
Rima Abi Saad
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Real Life ◽  
Geometric Design ◽  
Design Elements ◽  
Sight Distance ◽  
Human Driver ◽  
Projected Change ◽  
Vehicle Fleet ◽  
Stopping Sight Distance

This paper investigates the potential changes in the geometric design elements in response to a fully autonomous vehicle fleet. When autonomous vehicles completely replace conventional vehicles, the human driver will no longer be a concern. Currently, and for safety reasons, the human driver plays an inherent role in designing highway elements, which depend on the driver’s perception-reaction time, driver’s eye height, and other driver related parameters. This study focuses on the geometric design elements that will directly be affected by the replacement of the human driver with fully autonomous vehicles. Stopping sight distance, decision sight distance, and length of sag and crest vertical curves are geometric design elements directly affected by the projected change. Revised values for these design elements are presented and their effects are quantified using a real-life scenario. An existing roadway designed using current AASHTO standards has been redesigned with the revised values. Compared with the existing design, the proposed design shows significant economic and environmental improvements, given the elimination of the human driver.

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