Stopping Sight Distance and Available Sight Distance: New Model and Reliability Analysis Comparison

2017 ◽  
Vol 2638 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Jonathan S. Wood ◽  
Eric T. Donnell
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Design Criterion ◽  
Geometric Design ◽  
Design Criteria ◽  
Sight Distance ◽  
Stopping Sight Distance ◽  
Future Work ◽  
Important Design ◽  
Design Guidance

Stopping sight distance (SSD) is an important design criterion used in the geometry of highways and streets. Design guidance implies that SSD is used to ensure safety along the roadway. This paper reviews SSD design criteria and develops an updated model to improve consistency between available sight distance and SSD criteria found in geometric design policy. A new variable, the distance from the front of the car to the driver’s eye ( Lfront-eye), is used in the updated model. Distributional values for Lfront-eye are determined. A method accounting for lighted (daytime and lighted nighttime) versus unlighted nighttime conditions is also discussed. A probabilistic analysis of vertical curve SSD uses Monte Carlo simulation. The results of this analysis are compared with the SSD model found in current geometric design policy. Possible values for Lfront-eye that can be used in design guidance are proposed. Potential issues that should be investigated in future work are discussed.

Driver Eye and Vehicle Heights for Use in Geometric Design

1998 ◽  
Vol 1612 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Kay Fitzpatrick ◽  
Torsten Lienau ◽  
Daniel B. Fambro
Keyword(s):  
Geometric Design ◽  
Design Criteria ◽  
Passenger Cars ◽  
Passenger Car ◽  
Sight Distance ◽  
Total Vehicle ◽  
Vehicle Fleet ◽  
Stopping Sight Distance

Driver eye, headlight, taillight, and vehicle heights are important elements for determining passing and intersection sight distances and horizontal and vertical curve lengths to provide required stopping sight distance. Driver eye and object heights have varied significantly since their inception in the 1920s, when their values were suggested as 1676 mm. The objective of this study was to determine appropriate driver eye, headlight, taillight, and vehicle heights for use in developing geometric design criteria. The results of this research were used to recommend a driver eye height of 1080 mm for design purposes. This value represents 90 percent of the passenger car driver eye height values and an even higher percentage of the total vehicle fleet, because passenger cars have the lowest driver eye height values and represent fewer than two-thirds of the total vehicle fleet. Headlight and taillight heights of 600 mm are recommended for design. These values represent over 90 and 95 percent of the passenger cars observed in this study, respectively. The vehicle height recommendation for sight distance was 1315 mm, which represents the 10th percentile passenger car height values measured in the research.

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.

State-of-the-art of three-dimensional highway geometric design

1998 ◽  
Vol 25 (3) ◽  
pp. 500-511 ◽  
Author(s):  
Yasser Hassan ◽  
Said M Easa ◽  
A O Abd El Halim
Keyword(s):  
Traffic Safety ◽  
Vehicle Dynamics ◽  
Research Work ◽  
Three Dimensional ◽  
Computer Software ◽  
Design Criterion ◽  
Geometric Design ◽  
Analytical Models ◽  
Sight Distance ◽  
Current Standards

Geometric design is an important phase in the highway design process that is directly related to traffic safety. Highway elements should be jointly designed to account for such design criteria as sight distance, vehicle stability, driver comfort, drainage, and aesthetics. Intuitively, such a design should be based on a three-dimensional (3-D) analysis. This paper reviews the current practice and research work related to each design criterion with emphasis on the conformity with the 3-D nature of the highway. Current standards are based mainly on a two-dimensional (2-D) analysis that does not guarantee a satisfactory design. Recently, several research efforts have been expended in the 3-D highway analysis with sight distance being the most researched area. Analytical models and computer software have been developed to accurately model 3-D daytime and nighttime sight distances. Roads designed using current 2-D standards may compromise safety or economy. Different models are currently available to simulate the forces acting on a vehicle in 3-D. These models show that the point-mass formula for modelling vehicle dynamics in the current standards can be inaccurate. Current standards contain recommendations for drainage of surface water, but explicit quantitative coordination of combined alignments is lacking. Furthermore, research is still needed to study the effect of alignment coordination on highway aesthetics and driver's perception of information.Key words: highway geometric design, three-dimensional analysis, sight distance, vehicle dynamics, drainage, highway aesthetics.

scholarly journals 3D Sight Distance Calculation and Estimation of its Effect on Road Accidents in GIS Environment

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Ali Sahaf ◽  
Mostafa Mohammadi ◽  
Ali Abdoli
Keyword(s):  
Flow Speed ◽  
Geometric Design ◽  
Road Accidents ◽  
Factors Affecting ◽  
Sight Distance ◽  
Performance Error ◽  
Stopping Sight Distance ◽  
Gis Environment ◽  
Gis Software ◽  
Human Death

Nowadays, one of the main causes of human death is driving accidents. Across the world 1.2 million people die and several million people get injured annually as a result of road accidents. One of the main solutions that is important in resolving the problem of accidents is identifying the factors and their role and impact and the contribution of each in the accident. The stopping sight distance in the route is one of the initial factors in the driver’s performance error as well as the occurrence of an accident, financial losses, and deaths. The geometric design of roads is generally designed according to two-dimensional rules and regulations. Hence, today, given the remarkable advances in computer science and programming, there are many possibilities for 3D modeling of the route. Therefore, the calculation of the stopping sight distance should be based on existing facts and new scientific achievements. On the contrary, the stopping sight distance is one of the factors affecting driving crashes; therefore, this paper tries to investigate the accident occurrence probability in other spots of the existing route by calculating 3D stopping sight distance and using drivers’ free flow speed, as well as using the GIS software. In this way, the results of this study can pave the way for improving the geometric design of existing roads as well as prioritizing the correction of the accidental points of existing routes.

Sight distance evaluation on complex highway vertical alignments

1996 ◽  
Vol 23 (3) ◽  
pp. 577-586 ◽  
Author(s):  
Said M. Easa ◽  
Yasser Hassan ◽  
A. O. Abd El Halim
Keyword(s):  
Key Words ◽  
Geometric Design ◽  
Vertical Alignment ◽  
Common Tangent ◽  
Current Field ◽  
Analytical Methodology ◽  
Sight Distance ◽  
Stopping Sight Distance

Sight distance (stopping, passing, and decision) is a key element in highway geometric design. Existing models for evaluating sight distance on vertical alignments are applicable only to simple, isolated elements such as a crest vertical curve, a sag vertical curve, and a reverse vertical curve (a sag curve following a crest curve, or vice versa). This paper presents an analytical methodology for evaluating sight distance on complex vertical alignments that involve any combination of vertical alignment elements. The methodology can be used for evaluating passing sight distance on two-lane highways, and stopping sight distance and decision sight distance on all highways. Sight distance controlled by the headlight beam can also be evaluated. The locations of sight-hidden dips, which may develop when a sag vertical curve follows a crest vertical curve with or without a common tangent, can be determined. Also, sight distances obstructed by overpasses are evaluated. A profile of the available sight distance can be established and used to evaluate sight distance deficiency and the effect of alignment improvements. A software was developed and can be used for determining the available sight distance accurately. The software may replace the current field and graphical practice for establishing the no-passing zones and evaluating stopping and decision sight distances on complex vertical alignments. Key words: sight distance, vertical alignment, highway, passing zones.

Monte Carlo Simulation of Gas Spring in an Energy Storing Prosthetic Knee

2014 ◽  
Vol 660 ◽  
pp. 916-920
Author(s):  
Cucuk Nur Rosyidi ◽  
Rahmaniyah Dwi Astuti ◽  
Ilham Priadythama
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Quality Improvement ◽  
Significant Contribution ◽  
Prosthetic Knee ◽  
Cylinder Length ◽  
Cylinder Diameter ◽  
Design Variables ◽  
Important Design ◽  
Monte Carlo Simulation Model

Gas Spring is an important component of an energy storing prosthetic knee. The spring stored energy during flexion and released the energy while in the extension. In this research, we discuss a Monte Carlo simulation model of a gas spring in an Energy Storing Prosthetic Knee (ESPK) using Oracle Crystal Ball software. The simulation is used to predict the effects of three important design variables of a gas spring which are cylinder diameter, cylinder length, and displacement to the energy storing performance of the spring. The results of simulation show that there are two design variables which have significant contribution to the variations of energy storing performance: cylinder diameter and displacement. Those design variables account for 99.3% to the total variance of energy storing. Quality improvement must be conducted to lowering the resulted energy storing variance. We proportionally decrease the variance of the design variables to lowering the energy storing variance. The simulation results show a significant quality improvement of about 50% in term of energy storing standard deviation. The results also show that cylinder diameter is more sensitive than the other two design variables in energy storing quality improvement.

New Stopping Sight Distance Model for Use in Highway Geometric Design

2000 ◽  
Vol 1701 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Daniel B. Fambro ◽  
Kay Fitzpatrick ◽  
Rodger J. Koppa
Keyword(s):  
Geometric Design ◽  
Safe Driving ◽  
New Model ◽  
Basic Model ◽  
Sight Distance ◽  
Distance Model ◽  
Minimum Requirements ◽  
Design Values ◽  
Current Minimum ◽  
Stopping Sight Distance

Stopping sight distance is an important design parameter in that it defines the minimum sight distance that must be provided at all points along the highway. Thus, it influences geometric design values, construction costs, and highway safety. Stopping sight distance is defined as the sum of two components—brake reaction distance and braking distance. The basic model for calculating stopping sight distances was formalized in 1940, and the model’s parameters have been altered to compensate for changes in eye height, object height, and driver behavior over the past 50 years. Recent studies, however, question whether the model’s parameters and assumptions represent real-world conditions. A new model for determining stopping sight distance requirements for geometric design of highways is presented. This model is based on parameters describing driver and vehicle capabilities that can be validated with field data and defended as safe driving behavior. More than 50 drivers, 3,000 braking maneuvers, 1,000 driver eye heights, and 1,000 accident narratives were used to develop the recommended parameter values for the new model. The recommended values are attainable by most drivers, vehicles, and roadways. This model results in stopping sight distances, sag vertical curve lengths, and lateral clearances that are between the current minimum and desirable requirements and crest vertical curve lengths that are shorter than current minimum requirements.

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