Three-Dimensional Modelling of Deceleration and Acceleration Rates on Horizontal Curves of Two-Lane Rural Roads

2015 ◽  
pp. 57-69 ◽  
Author(s):  
Hatem Mahmoud ◽  
Dalia Said ◽  
Laila Radwan
Keyword(s):  
Three Dimensional ◽  
Rural Roads ◽  
Horizontal Curves

scholarly journals Speed Models for Motorcycle Riders for Two-lane Rural Roads

2021 ◽  
Vol 17 ◽  
pp. 595-603
Author(s):  
Panagiotis Lemonakis ◽  
George Botzoris ◽  
Athanasios Galanis ◽  
Nikolaos Eliou
Keyword(s):  
Prediction Models ◽  
Flow Speed ◽  
Operating Speed ◽  
Rural Roads ◽  
The Road ◽  
Horizontal Curves ◽  
Road Geometry ◽  
Speed Prediction ◽  
The Subject ◽  
On The Road

The development of operating speed models has been the subject of numerous research studies in the past. Most of them present models that aim to predict free-flow speed in conjunction with the road geometry at the curved road sections considering various geometric parameters e.g., radius, length, preceding tangent, deflection angle. The developed models seldomly take into account the operating speed profiles of motorcycle riders and hence no significant efforts have been put so far to associate the geometric characteristics of a road segment with the speed behavior of motorcycle riders. The dominance of 4-wheel vehicles on the road network led the researchers to focus explicitly on the development of speed prediction models for passenger cars, vans, pickups, and trucks. However, although the motorcycle fleet represents only a small proportion of the total traffic volume motorcycle riders are over-represented in traffic accidents especially those that occur on horizontal curves. Since operating speed has been thoroughly documented as the most significant precipitating factor of vehicular accidents, the study of motorcycle rider's speed behavior approaching horizontal curves is of paramount importance. The subject of the present paper is the development of speed prediction models for motorcycle riders traveling on two-lane rural roads. The model was the result of the execution of field measurements under naturalistic conditions with the use of an instrumented motorcycle conducted by experienced motorcycle riders under different lighting conditions. The implemented methodology to determine the most efficient model evaluates a series of road geometry parameters through a comprehensive literature review excluding those with an insignificant impact to the magnitude of the operating speeds in order to establish simple and handy models.

Relationship between Predicted Speed Reduction on Horizontal Curves and Safety on Two-Lane Rural Roads in Spain

2014 ◽  
Vol 140 (3) ◽  
pp. 04013015 ◽  
Author(s):  
Juan de Oña ◽  
Laura Garach ◽  
Francisco Calvo ◽  
Teresa García-Muñoz
Keyword(s):  
Rural Roads ◽  
Speed Reduction ◽  
Horizontal Curves

Speeds of Cars on Horizontal Curves

1998 ◽  
Vol 1612 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Vojo Andjus ◽  
Mihailo Maletin
Keyword(s):  
Free Flow ◽  
Flow Conditions ◽  
Passenger Cars ◽  
Design Standards ◽  
Rural Roads ◽  
Horizontal Curves ◽  
Road Design ◽  
Realistic Approach ◽  
Actual Design ◽  
Design Speed

Revision of existing Yugoslav road-design standards, specifically in the area of road-design speed definition, required studying driver behavior in free-flow conditions in order to define drivers’ responses to the radii of horizontal curves. A specific approach with variable design speed for horizontal curves is discussed and is supported by speed measurements on roads. The pilot research was undertaken on several test sites on Yugoslav two-lane rural roads to collect reliable speed data related to characteristics of horizontal curves. Characteristics of test sites, experimental procedures, data collected, and results of data analyses are described. It is concluded that speeds of free-flow passenger cars show good correlation with radii and that actual design policy with a constant design speed underestimates speeds in radii less than 250 m. Thus, the variable design speed concept is a more realistic approach. Further research on more test sites is recommended.

Design radius requirements for simple horizontal curves on three-dimensional alignments

2003 ◽  
Vol 30 (6) ◽  
pp. 1022-1033 ◽  
Author(s):  
Said M Easa ◽  
Essam Dabbour
Keyword(s):  
Three Dimensional ◽  
Design Guidelines ◽  
Comfort Level ◽  
Vertical Alignment ◽  
Passenger Cars ◽  
Minimum Radius ◽  
Horizontal Curves ◽  
Design Speed ◽  
Side Friction ◽  
Mathematical Relationships

Current North American design guides have established mathematical relationships to calculate the minimum radius required for horizontal curves as a function of design speed, maximum superelevation, and maximum side friction. For three-dimensional (3-D) alignments, the design guides consider the alignment as two separate horizontal and vertical alignments and consequently ignore the effect of vertical alignment. This paper evaluates the effect of vertical alignment on minimum radius requirements using computer simulation, with a focus on trucks. For 3-D alignments, the results showed that existing design guidelines for minimum radius need to be increased by as much as 20% to achieve the same comfort limit on flat horizontal curves. It is interesting to note that in some cases truck rollover occurred before the side-friction comfort level is reached. This indicates the need for developing a different design control for trucks on 3-D alignments than the comfort criterion used for passenger cars on flat horizontal curves. Based on the simulation results, mathematical models for design radius requirements for passenger cars and trucks were developed.Key words: geometric design, horizontal curve radius, three-dimensional alignments, vehicle stability.

scholarly journals Truck stability on different types of horizontal curves combined with vertical alignments

2021 ◽  
Author(s):  
Essam Mohamed S. A. E. A. Dabbour
Keyword(s):  
Three Dimensional ◽  
Computer Software ◽  
Design Guidelines ◽  
Vehicle Stability ◽  
Horizontal Curves ◽  
Different Types ◽  
Current Design ◽  
Single Compound ◽  
Margin Of Safety ◽  
Design Speed

The combination of horizontal curves with vertical alignments is commonly used in different classifications of highways; either on highway mainstream or on highway interchange ramps. The horizontal curves, combined with vertical alignments, may be single, compound or reverse horizontal curves. The current design guidelines do not adequately investigate vehicle stability on such three-dimensional (3D) alignments. Computer software that simulates vehicle behaviour on different geometrical alignments was employed to investigate vehicle stability on such 3D alignments. It was found that vehicle safety is questionable, especially for larger vehicles on reverse curves associated with vertical alignments. The critical speed, where the vehicle starts to rollover or skid, was found to be close to design speed for those 3D alignments. Design aids were then developed to address the recommended solutions to maintain the margin of safety required.

scholarly journals ROAD SURFACE DETECTION FROM MOBILE LIDAR DATA

2018 ◽  
Vol IV-5 ◽  
pp. 95-101 ◽  
Author(s):  
M. Yadav ◽  
B. Lohani ◽  
A. K. Singh
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Test Site ◽  
Road Surface ◽  
Lidar Data ◽  
Rural Roads ◽  
The Road ◽  
Surface Detection ◽  
Rural Road ◽  
Data Points

<p><strong>Abstract.</strong> The accurate three-dimensional road surface information is highly useful for health assessment and maintenance of roads. It is basic information for further analysis in several applications including road surface settlement, pavement condition assessment and slope collapse. Mobile LiDAR system (MLS) is frequently used now a days to collect detail road surface and its surrounding information in terms three-dimensional (3D) point cloud. Extraction of road surface from volumetric point cloud data is still in infancy stage because of heavy data processing requirement and the complexity in the road environment. The extraction of roads especially rural road, where road-curb is not present is very tedious job especially in Indian roadway settings. Only a few studies are available, and none for Indian roads, in the literature for rural road detection. The limitations of existing studies are in terms of their lower accuracy, very slow speed of data processing and detection of other objects having similar characteristics as the road surface. A fast and accurate method is proposed for LiDAR data points of road surface detection, keeping in mind the essence of road surface extraction especially for Indian rural roads. The Mobile LiDAR data in <i>XYZI</i> format is used as input in the proposed method. First square gridding is performed and ground points are roughly extracted. Then planar surface detection using mathematical framework of principal component analysis (PCA) is performed and further road surface points are detected using similarity in intensity and height difference of road surface pointe in their neighbourhood.</p><p>A case study was performed on the MLS data points captured along wide-street (two-lane road without curb) of 156<span class="thinspace"></span>m length along rural roadway site in the outskirt of Bengaluru city (South-West of India). The proposed algorithm was implemented on the MLS data of test site and its performance was evaluated it terms of recall, precision and overall accuracy that were 95.27%, 98.85% and 94.23%, respectively. The algorithm was found computationally time efficient. A 7.6 million MLS data points of size 27.1<span class="thinspace"></span>MB from test site were processed in 24 minutes using the available computational resources. The proposed method is found to work even for worst case scenarios, i.e., complex road environments and rural roads, where road boundary is not clear and generally merged with road-side features.</p>

The Effects of Edgeline Presence on Performance in a Driving Simulator under Sober and Alcohol-Dosed Conditions

1983 ◽  
Vol 27 (4) ◽  
pp. 329-329
Author(s):  
Thomas A. Ranney ◽  
Valerie J. Gawron
Keyword(s):  
Visual Information ◽  
Driving Simulator ◽  
Lateral Acceleration ◽  
Task Demand ◽  
Rural Roads ◽  
Pavement Markings ◽  
Horizontal Curves ◽  
Varying Length ◽  
Alcohol Effects ◽  
And Performance

Accident studies have identified nighttime conditions on rural roads as particular problems for alcohol-impaired drivers. Uneventful driving is hypothesized to result in progressive degradation of tracking performance and a reduced capability to handle the demands of hazardous locations, such as curves. To address these problems, simulations of continuous roadway treatments (i.e., wide edge lines) and spot treatments for curves (i.e., post delineators, chevron alignment signs, patterned pavement markings, and flashing displays) were evaluated experimentally. Twelve subjects drove a simulator under two conditions of task demand and three levels of BAC (0.0, 0.07, 0.12%). The objectives of the study were to determine the effects of alcohol and task demand on driving performance and to determine if providing enhanced visual information concerning roadway alignment would improve the performance of subjects when sober and/or alcohol-dosed. Alcohol effects were measured in terms of overall scenario performance, which included the number of accidents and speed exceedances, and performance on the approach and negotiation of horizontal curves of varying length and curvature. Curve approach and negotiation behavior were also used to evaluate the effects of the roadway treatments. Specific measures included spot measures of speed and lateral placement taken at eight 100-foot intervals along the curve approach and lateral acceleration and position taken continuously over the fixed portion of the curves. The results presented pertain to the effects of the presence of standard and wide edgelines. The discussion relates current findings to those from a previously conducted study.

Analytical Model for Sight Distance Analysis on Three-Dimensional Highway Alignments

1996 ◽  
Vol 1523 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Yasser Hassan ◽  
Said M. Easa ◽  
A. O. Abd El Halim
Keyword(s):  
Three Dimensional ◽  
The Finite Element Method ◽  
Horizontal Curve ◽  
Design Standards ◽  
New Model ◽  
Distance Analysis ◽  
Horizontal Curves ◽  
Sight Distance ◽  
Proposed Model ◽  
Standards And Guidelines

Existing sight distance models are applicable only to two-dimensional (2-D) separate horizontal and vertical alignments or simple elements of these separate alignments (vertical curve, horizontal curve). A new model is presented for determining the available sight distance on 3-D combined horizontal and vertical alignments. The model is based on the curved parametric elements that have been used in the finite element method. The elements presented are rectangular (4-node, 6-node, and 8-node elements) and triangular. These elements are used to represent various features of the highway surface and sight obstructions, including tangents (grades), horizontal curves, vertical curves, traveled lanes, shoulders, side slopes, cross slopes, superelevation, lateral obstructions, and overpasses. The available sight distance is found analytically by examining the intersection between the sight line and the elements representing the highway surface and the sight obstructions. Application of the new model is illustrated using numerical examples, and the results show that existing 2-D models may underestimate or overestimate the available sight distance. The proposed model should be valuable in establishing design standards and guidelines for 3-D highway alignments and determining the effect of various highway features on sight distance.

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