scholarly journals An Intelligent and Autonomous Sight Distance Evaluation Framework for Sustainable Transportation

2021 ◽  
Vol 13 (16) ◽  
pp. 8885
Author(s):  
Vivek Singhal ◽  
Divya Anand ◽  
Hani Moaiteq Aljahdali ◽  
Nitin Goyal ◽  
Aman Singh ◽  
...  
Keyword(s):  
Sustainable Transportation ◽  
Evaluation Framework ◽  
Supervised Machine Learning ◽  
Level Crossings ◽  
Road Vehicle ◽  
Accident Prediction ◽  
Rail Track ◽  
Sight Distance ◽  
Distance Model ◽  
Stopping Sight Distance

Railways are facing a serious problem of road vehicle–train collisions at unmanned railway level crossings. The purpose of the study is the development of a safe stopping sight distance and sight distance from road to rail track model with appropriate computation and analysis. The scope of the study lies in avoiding road vehicle–train collisions at unmanned railway level crossings. An intelligent and autonomous framework is being developed using supervised machine learning regression algorithms. Further, a sight distance from road to rail track model is being developed for road vehicles of 0.5 to 10 m length using the observed geometric characteristics of the route. The model prediction accuracy obtained better results in the development of a stopping sight distance model in comparison to other intelligent algorithms. The developed model suggested an increment of approximately 23% in the current safe stopping sight distance on all unmanned railway level crossings. Further, the feature analysis indicates the ‘approach road gradient’ to be the major contributing parameter for safe stopping sight distance determination. The accident prediction study finally indicates that, as the safe stopping sight distance is increased by following the developed model, it is predicted to decrease road vehicle–train collisions.

Sight Distance for Stop-Controlled Intersections Based on Gap Acceptance

2000 ◽  
Vol 1701 (1) ◽  
pp. 32-41 ◽  
Author(s):  
Douglas W. Harwood ◽  
John M. Mason ◽  
Robert E. Brydia
Keyword(s):  
Travel Time ◽  
Field Studies ◽  
Major Road ◽  
Gap Acceptance ◽  
Road Vehicle ◽  
Sight Distance ◽  
Minor Road ◽  
Distance Model ◽  
Design Speed ◽  
A Minor

The current AASHTO policy for sight distance at Stop-controlled intersections is based on a model of the acceleration performance of a minor-road vehicle turning left or right onto a major road and the deceleration performance of the following major road vehicle. An alternative intersection sight distance model based on gap acceptance is developed and quantified. Field studies that were performed to determine the critical gaps appropriate for use in sight distance design are described. It is recommended that the sight distance along the major road for a passenger car at a Stop-controlled intersection should be based on a distance equal to 7.5 s of travel time at the design speed of the major road. Longer sight distances are recommended for minor-road approaches that have sufficient truck volumes to warrant consideration of a truck as the design vehicle.

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.

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 Study of Drivers’ Behaviour at a Passive Railway Crossing

1970 ◽  
Vol 24 (3) ◽  
pp. 193-201 ◽  
Author(s):  
Sandra Kasalica ◽  
Radisav Vukadinović ◽  
Vojkan Lučanin
Keyword(s):  
Observational Study ◽  
Road Traffic ◽  
Level Crossing ◽  
Level Crossings ◽  
Road Vehicle ◽  
Railway Crossing ◽  
Limited Visibility ◽  
Risky Decisions

Problem: The number of killed and injured persons in incidents at railway level crossings is generally increasing on the Serbian Railways, particularly at passive crossings. In this paper we researched the direct behaviour of road traffic participants at a conventional railway passive crossing. Method: Direct observational study of drivers’ behaviour at a level crossing. Results: Sixty-one road vehicle drivers were observed in the moments of train approach. The probability of crossing varies depending on the train distance and the time the driver has to cross the crossing. The drivers who have limited visibility cannot estimate the speed of the approaching train well and make more risky decisions. Conclusion: This study shows that the number of “risky crossings” is worrying as the result of such crossings is a large number of accidents with fatal consequences at the passive crossings in Serbia.

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.

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.

Location-based analysis of car-following behavior during braking using naturalistic driving data

2020 ◽  
Vol 47 (5) ◽  
pp. 498-505 ◽  
Author(s):  
Mostafa H. Tawfeek ◽  
Karim El-Basyouny
Keyword(s):  
Driver Assistance Systems ◽  
Behavioral Measures ◽  
Car Following ◽  
Sight Distance ◽  
Influence Area ◽  
Data Source ◽  
Naturalistic Driving ◽  
Stopping Sight Distance ◽  
Microscopic Modeling ◽  
Rich Data

This study investigates the car-following behavior during braking at intersections and segments. Car-following events were extracted from a naturalistic driving dataset, mapped using ArcGIS, and analyzed to differentiate between the intersection- and segment-related events. The intersection-related events were identified according to an intersection influence area, which was estimated based on the stopping sight distance and the speed limit. Five behavioral measures were quantified based on exploring the probability density functions (PDF) for intersection- and segment-related events. The results showed that there were significant differences between the PDFs of the measures for both cases. Moreover, it was indicated that drivers tend to be more aggressive at intersections compared with segments. Thus, it is crucial to consider the driver’s location when investigating driver behavior. The quantified behavioral measures are a rich data source that can be used for car-following microscopic modeling, surrogate safety analysis, and driver assistance systems development.

Motorcyclist perception response time in stopping sight distance situations

2012 ◽  
Vol 50 (3) ◽  
pp. 371-377 ◽  
Author(s):  
Seyed Rasoul Davoodi ◽  
Hussain Hamid ◽  
Mahdieh Pazhouhanfar ◽  
Jeffrey W. Muttart
Keyword(s):  
Response Time ◽  
Sight Distance ◽  
Stopping Sight Distance
Sign in / Sign up

Export Citation Format

Share Document