Traffic and speed characteristics on two-lane highways: field study

2003 ◽  
Vol 30 (6) ◽  
pp. 1042-1054 ◽  
Author(s):  
Yasser Hassan
Keyword(s):  
Light Condition ◽  
Operating Speed ◽  
Ambient Light ◽  
Horizontal Curve ◽  
Vehicle Class ◽  
Rural Highways ◽  
Horizontal Alignment ◽  
Heavy Truck ◽  
Traffic Composition ◽  
Rural Highway

Many models have been developed to evaluate the operating speeds on two-lane rural highways. However, provided information usually lacks details essential to assess their applicability at locations other than where they were developed. This paper presents a procedure to interpret raw data collected on three horizontal curve sites of different two-lane rural highway classes in Ontario. The speed observations were categorized into three vehicle classes (passenger car, light truck, and multi-axle heavy truck) and four light condition categories (day, night, and two transition periods). The minimum headway and percentile value to define the operating speed were examined, and a revision of the current practice deemed not warranted. The findings also indicated that operating speeds do not depend on the time or vehicle class. Finally, the horizontal alignment affects the operating speed, but the speeds of the two travel directions on a horizontal curve may differ even with little contribution of the vertical alignment.Key words: highway geometric design, operating speed, traffic composition, traffic counters, ambient light, acceleration, deceleration.

Evaluating Horizontal Alignment Design Consistency of Two-Lane Rural Highways: Development of New Procedure

2000 ◽  
Vol 1737 (1) ◽  
pp. 9-17 ◽  
Author(s):  
John McFadden ◽  
Lily Elefteriadou
Keyword(s):  
Primary Objective ◽  
Maximum Speed ◽  
Operating Speed ◽  
Speed Profile ◽  
Horizontal Curve ◽  
Rural Highways ◽  
Speed Reduction ◽  
Design Elements ◽  
The Difference ◽  
Design Consistency

Design consistency refers to the condition wherein the roadway geometry does not violate driver expectations. Operating-speed profile models are used to evaluate the consistency of a design by identifying locations with large speed variability between successive design elements. There is a direct correlation between safety and variability in speeds. Recent operating-speed models predict the 85th percentile speeds on horizontal curves and compare this value with the expected 85th percentile speed on the approach tangent. There is a direct correlation between speed variability between successive design elements and crash rates. Eighty-fifth percentile speeds, however, do not necessarily represent the speed reductions experienced by drivers. The primary objective of the research was to assess the efficacy of the use of 85th percentile speed by operating-speed profile models to evaluate the consistency of a design. Speed data were collected at 21 horizontal curve sites. These data were used to evaluate the implication of using 85th percentile speed for evaluating design consistency. A new parameter was investigated for analyzing design consistency: the 85th percentile maximum reduction in speed (85MSR). This parameter is calculated by using each driver’s speed profile from an approach tangent through a horizontal curve and determining the maximum speed reduction each driver experiences. These maximum speed reductions are sorted, and the 85th percentile value becomes the statistic of interest, or 85MSR. 85MSR was compared with the difference in 85th percentile speeds (85S), and it was found that 85MSR is significantly larger than 85S. The data showed that, on average, 85MSR is approximately two times larger than 85S. Models were developed that predict 85MSR as a function of geometric design elements, and these models could be used to complement existing operating-speed models.

scholarly journals Comparison of consistency assessment models for isolated horizontal curves in two-lane rural highways

DYNA ◽  
2015 ◽  
Vol 82 (194) ◽  
pp. 57-65
Author(s):  
Danilo Cárdenas-Aguilar ◽  
Tomás Echaveguren
Keyword(s):  
Spatial Variation ◽  
Operating Speed ◽  
Speed Profile ◽  
Horizontal Curve ◽  
Spatial Variance ◽  
Middle Point ◽  
Rural Roads ◽  
Rural Highways ◽  
Horizontal Curves ◽  
The Difference

This consistency assessment of highways’ geometrical design has the objective of providing safer roads. There are two types of models for consistency assessment: aggregated and disaggregated. The first one considers the difference between design and operating speed at the middle point of isolated horizontal curves. The second one considers the spatial variation of the operating speed profile along the horizontal curve. This paper compares the two types of consistency assessment models, using naturalistic speed and geometry data obtained in 34 horizontal curves of two-lane rural roads in Chile, using a 10 Hz GPS. Results obtained showed that in only 19 cases both methods are equivalent. This equivalence occurred only when operating speed profiles have the lowest spatial variance along the curves. If the operating speed profile has a high variance the consistency level obtained using both methods is different and the better option is combine it.

Operating Speed Modeling for the Rural Highways Passing through Hilly Terrain

2021 ◽  
Vol 147 (5) ◽  
pp. 04021015
Author(s):  
R. D. K. Shallam ◽  
Suvin P. Venthuruthiyil ◽  
Mallikarjuna Chunchu ◽  
Anjan Kumar Siddagangaiah
Keyword(s):  
Operating Speed ◽  
Hilly Terrain ◽  
Rural Highways

Investigation of Motorcycle Trajectories in 2-lane Horizontal Curves

2021 ◽  
Vol 16 ◽  
pp. 610-625
Author(s):  
Panagiotis Lemonakis
Keyword(s):  
Linear Equations ◽  
Great Accuracy ◽  
Design Guidelines ◽  
Road Segment ◽  
Small Radius ◽  
Horizontal Curve ◽  
Horizontal Alignment ◽  
The Road ◽  
Horizontal Curves ◽  
Traffic Lane

Most of the road design guidelines assume that the vehicles traverse a trajectory that coincides with the midline of the traffic lane. Based on this assumption the thresholds of various features are determined such as the maximum permissible side friction factor. It is therefore important to investigate the extent to which the trajectory of the vehicles is similar to the horizontal alignment of the road or substantial differences exist. To this end, a naturalistic riding study was designed and executed with the use of an instrumented motorcycle which measured the position of the motorcycle with great accuracy in a rural 2-lane road segment. The derived trajectories were then plotted against the horizontal alignment of the road and compared with the 3 consecutive elements which form a typical horizontal curve i.e., the entering spiral curve, the circular curve, and the exiting spiral curve. Linear equations were developed which correlate the traveled curvatures with the distance of each horizontal curve along the road segment under investigation. The process of the data revealed that the riders differ their trajectory compared to the alignment of the road. However, in small radius horizontal curves is more likely to observe curvatures that are similar to the geometric one. Moreover, the riders perform more abrupt maneuvres in the first part of the horizontal curves while they straighten the handlebars of the motorcycle before the end of the curve. The present paper aims to shed light on the behavior of motorcycle riders on horizontal curves and hence to contribute to the reduction of motorcycle accidents, particularly the single-vehicle ones.

Modeling Operating Speed Using Continuous Speed Profiles on Two-Lane Rural Highways in India

2020 ◽  
Vol 146 (11) ◽  
pp. 04020124
Author(s):  
Vinayak Malaghan ◽  
Digvijay S. Pawar ◽  
Hussein Dia
Keyword(s):  
Operating Speed ◽  
Rural Highways

Guidelines for Right-Turn Treatments at Unsignalized Intersections and Driveways on Rural Highways

1997 ◽  
Vol 1579 (1) ◽  
pp. 63-72
Author(s):  
Tanweer Hasan ◽  
Robert W. Stokes
Keyword(s):  
Economic Analysis ◽  
Cost Savings ◽  
Operating Speed ◽  
Full Width ◽  
Rural Highways ◽  
Unsignalized Intersections ◽  
Traffic Volumes ◽  
The Right ◽  
Design Hourly Volume ◽  
The Relationship

Guidelines for right-turn treatments at unsignalized intersections and driveways on rural two-lane and four-lane highways are presented. Two types of treatments, full-width lane and taper, were considered over the do-nothing radius treatment. The guidelines indicate the design hourly traffic volumes for which the benefits of right-turn treatments exceed their costs. The benefits used in the economic analysis were the operational and accident cost savings provided by right-turn treatments. The costs used in the development of the guidelines were the costs of constructing full-width right-turn lanes and tapers. The operational effects were estimated in terms of delay and excess fuel consumption experienced by through traffic due to right-turning vehicles. To account for the safety effects, the relationship between speed differential and accidents was used to estimate the reduction in right-turn, same-direction, rear-end accidents that would be expected to result from the provision of a right-turn treatment. The guidelines indicate the right-turn design hourly volume required to justify a right-turn treatment as a function of the following factors: ( a) directional design hourly volume, (b) highway operating speed, and ( c) number of lanes on the highway. Comparisons with other guidelines indicate that the range of guidelines developed are reasonable. In addition, they are more definitive than other guidelines because they account for highway operating speed and address taper treatments as well as full-width turn lanes.

A Voxel-Based Method for Automated Detection and Mapping of Light Poles on Rural Highways using LiDAR Data

2018 ◽  
Vol 2672 (45) ◽  
pp. 274-283 ◽  
Author(s):  
Suliman A. Gargoum ◽  
James C. Koch ◽  
Karim El-Basyouny
Keyword(s):  
Decision Rules ◽  
Automated Detection ◽  
Connected Components ◽  
Point Cloud Data ◽  
Vertical Alignment ◽  
Safe Operation ◽  
Rural Highways ◽  
Cloud Data ◽  
Density Based Clustering ◽  
Rural Highway

The number of light poles and their position (in terms of density and offset off the roadside) have significant impacts on the safe operation of highways. In current practice, inventory of such information is performed in periodic site visits, which are tedious and time consuming. This makes inventory and health monitoring of poles at a network level extremely challenging. To relieve the burden associated with manual inventory of poles, this paper proposes a novel algorithm which can automatically obtain such information from remotely sensing data. The proposed algorithm works by first tiling point cloud data collected using light detection and ranging (LiDAR) technology into manageable data tiles of fixed dimensions. The data are voxelized and attributes for each data voxel are calculated to classify them into ground and nonground points. Connected components labeling is then used to perform 3D clustering of the data voxels. Further clustering is performed using a density-based clustering to combine connected components of the same object. The final step involves classifying different objects into poles and non-poles based on a set of decision rules related to the geometric properties of the clusters. The proposed algorithm was tested on a 4 km rural highway segment in Alberta, Canada, which had substantial variation in its vertical alignment. The algorithm was accurate in detecting nonground objects, including poles. Moreover, the results also highlight the importance of considering the length of the highway and its terrain when detecting nonground objects from LiDAR.

scholarly journals Evaluation of Visual Comfort and Mental Effort Under Different Light Conditions for Ultraviolet-Absorbing and Additional Blue-Filtering Intraocular Lenses for Cataract Surgery

2019 ◽  
Vol 236 (04) ◽  
pp. 398-404 ◽  
Author(s):  
Alexandra Steinemann ◽  
Vivien Bromundt ◽  
Sarah Chellappa ◽  
Sylvia Frey ◽  
Christina Schmidt ◽  
...  
Keyword(s):  
Intraocular Lens ◽  
Mixed Model ◽  
Rating Scale ◽  
Light Condition ◽  
Mental Effort ◽  
Intraocular Lenses ◽  
Visual Comfort ◽  
Ambient Light ◽  
Mixed Model Analysis ◽  
Potential Benefits

Abstract Patients and Methods Patients with an ultraviolet blocking lens (UV) (n = 5) or blue filter lens (BB) (n = 8) after intraocular lens (IOL) replacement for cataract and age-adjusted controls (AACs) (n = 16) underwent a balanced crossover within-subject design. After 1.5 h of dark adaptation, they were exposed to polychromatic light at 6500 K (blue-enriched) and 2500 K and 3000 K (non-blue-enriched) for 2 hours in the evening. Visual comfort and mental effort were repeatedly assessed by the Visual Analogue Scale (0 – 100) and the Visual Comfort and Mental Effort Rating Scale (0 – 100) for each light condition. The results were compared using mixed model analysis. Results The mean (± SD) age for AAC and patients with UV or BB was 69.8 ± 6.2 y, 70.8 ± 4 y, and 63.6 ± 5.6 y, respectively. Irrespective of the light condition, patients with UV and BB felt mentally more tired during the experiments compared to AACs (F = 6.15, p = 0.003). However, patients with BB were mentally more motivated to perform the exercises compared to patients with UV and AACs (F = 8.1, p < 0.001). Patients with BB perceived ambient light as less glary (F = 4.71, p = 0.01) than patients with UV. Blue ambient light was felt less intensely in patients with BB (F = 2.51, p = 0.042) compared to those with UV and the AACs. Conclusion Lens replacement in older cataract patients may increase visual comfort and minimize mental effort. While subtle, the magnitude of these effects may depend on the type of intraocular lens. BB intraocular lenses may have potential benefits, as ambient light is perceived as having less glare and less visual tension.

Comparison of Radius-Estimating Techniques for Horizontal Curves

2005 ◽  
Vol 1918 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Paul J. Carlson ◽  
Mark Burris ◽  
Kit Black ◽  
Elisabeth R. Rose
Keyword(s):  
Global Positioning System ◽  
Ease Of Use ◽  
Horizontal Curve ◽  
Rural Highways ◽  
Horizontal Curves ◽  
Long Run ◽  
Wide Range ◽  
Global Positioning ◽  
Advisory Speed ◽  
Transportation Agencies

Techniques to obtain horizontal curve radii were identified and tested in a controlled experimental study. Ten techniques were identified and pilot tested. Eight of those initial 10 were then used to measure 18 horizontal curves on two-lane rural highways in Texas to evaluate fully their accuracy, precision, cost, ease of use, and safety. Statistically, all eight techniques produced equivalent accuracies, but they displayed a wide range in their precision. The costs varied as a function of the number of times each technique would be used in the field, with those techniques with high initial costs becoming more cost-competitive over the long run with many uses. Ease of use was gauged on the basis of the experience gained during this research. Safety was measured on the basis of whether a technique required personnel on the roadway or roadside or whether it allowed personnel to work from an office or inside a vehicle. The recommendations were based on the expected needs of three different groups that use radii information: transportation agencies, accident investigators, and transportation researchers. Within transportation agencies, engineers and planners in the office will probably benefit most from the plan sheet method, whereas field personnel will probably benefit most from using either the advisory speed or a Global Positioning System (GPS) method. Those who estimate only occasionally, such as accident investigators, will benefit most from the compass method. Finally, researchers or others who may have difficulty accessing plan sheets but still require accurate data will benefit from using a GPS.

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