Influence of Road Geometric Design Consistency on Familiar and Unfamiliar Drivers’ Performances: Crash-Based Analysis

2019 ◽  
Vol 2673 (10) ◽  
pp. 489-500 ◽  
Author(s):  
Paolo Intini ◽  
Nicola Berloco ◽  
Pasquale Colonna ◽  
Sofie Ottersland Granås ◽  
Eirin Olaussen Ryeng
Keyword(s):  
Experimental Studies ◽  
Related Factor ◽  
Design Elements ◽  
Safety Issues ◽  
Vehicle Accidents ◽  
Road Design ◽  
Dangerous Behavior ◽  
Run Off ◽  
Single Vehicle ◽  
Design Consistency

Drivers’ road familiarity is a safety-related factor. Familiar drivers may be prone to inattention and more dangerous behavior, whereas unfamiliar drivers may be affected by demanding and unexpected road environments. Previous research adequately described the role of familiarity in driving behavior and road safety performances. However, the relationships between drivers’ unfamiliarity and safety issues of road design elements are still largely unexplored and there is a lack of dedicated experimental studies. In this work, a database including run-off-road single-vehicle accidents at Norwegian rural two-lane road curves was investigated. Information about familiarity was derived from the distance from the residence of drivers involved in crashes. Road geometric variables were collected on the segment before the accident site, to provide indicators of design consistency of the previous road section. Thereafter, logistic regression was used to find relationships between predictor variables related to the geometric road design consistency and familiarity (the dependent variable). As a result of the analysis, familiarity was confirmed as a factor associated to possible dangerous behavior such as speeding in demanding road environments. However, crashes involving unfamiliar drivers are associated to unexpected curve parameters (radius and length) and the combination of horizontal and vertical curvature. Thus, as well as familiarity, drivers’ unfamiliarity may be considered as an accident factor. Moreover, some possibly useful consequences for road design are suggested for practitioners. They specifically concern provisions about radii of subsequent curves and coordination between radii of horizontal and vertical curves.

scholarly journals Empirical Speed Behavior on Horizontal Ramp Curves in Interchanges in the Netherlands

2017 ◽  
Vol 2618 (1) ◽  
pp. 38-47 ◽  
Author(s):  
Haneen Farah ◽  
Aries van Beinum ◽  
Winnie Daamen
Keyword(s):  
The Netherlands ◽  
Prediction Models ◽  
Operating Speed ◽  
Trajectory Data ◽  
Design Elements ◽  
The Road ◽  
Road Design ◽  
Speed Prediction ◽  
Design Consistency ◽  
High Level

Several studies in the literature have indicated that interchanges are the most crash-prone areas within the motorway system in number and severity of accidents. The reason is the high level of turbulence as a result of vehicle lane changes and speed variability. To understand the safety consequences of an interchange design (e.g., type of connecting ramps, radii and superelevation of curves, and lane and shoulder widths), an in-depth investigation of driving speed behavior is needed. Such an investigation requires the collection of detailed trajectory data on vehicles on different interchanges. These types of data are rarely available, and as a result, such studies are scarce in the literature. The main objective of this present study was to analyze driver speed behavior on different ramps at interchanges, and to develop an operating speed prediction model as a function of the road design elements. Trajectory data on free-moving vehicles were derived from stabilized video images taken from a camera mounted underneath a helicopter, which hovered over the road areas studied. Data were collected from 29 curves at six freeway–freeway interchanges in the Netherlands. The sample included nine direct connections, 12 semidirect connections, and eight indirect connections. The findings showed that speeds were affected by several road geometric characteristics of the curves, by driver expectancy and design consistency, and by the percentage of trucks in traffic. The operating speed prediction models developed in the study will provide designers with tools to estimate the operating speed during the design process.

Driving Dynamic Aspects and Related Safety Issues for Modern Geometric Design of Non-Built-Up Roads

1996 ◽  
Vol 1523 (1) ◽  
pp. 34-45
Author(s):  
Ruediger Lamm ◽  
Basil Psarianos ◽  
George Soilemezoglou ◽  
George Kanellaidis
Keyword(s):  
Geometric Design ◽  
Driving Dynamic ◽  
Safety Criterion ◽  
Rural Roads ◽  
Safety Issues ◽  
Road Design ◽  
Friction Factors ◽  
The Status ◽  
Design Consistency ◽  
Side Friction

Safety issues affecting modern highway geometric design of roads in non-built-up areas are discussed. The status of knowledge of Safety Criteria I and II (achieving operating speed consistency and design consistency) for two-lane rural roads is briefly reviewed. Considerations for design consistency are also extended to multiple-lane rural and suburban road design to evaluate good, fair, and poor design levels for these road categories. Utilization ratios (n) for maximum permissible side friction factors are developed for different road categories, topography levels, and maximum and minimum superelevation rates. Relevant minimum radii for curve design are established and compared with present AASHTO values insofar as possible. Safety Criterion III (achieving driving dynamic consistency) is further developed, through which reliable and quantitative ranges between the side friction assumed and the actual friction demand at curved sites could be established. AASHTO's design policy is evaluated on the basis of Criteria II and III. The evaluation showed, for lower design speeds (30, 40, and 50 mph), an unbalanced degree of curve and superelevation rate ranges, which lead to poor design practices from a safety viewpoint. By heeding the three safety criteria and the recommended side-friction utilization ratios, sound alignments can be established for the various design cases in future highway geometric design and redesign and for resurfacing, restoration, and rehabilitation strategies.

scholarly journals EXPERIMENTAL RELATIONSHIPS BETWEEN OPERATING SPEEDS OF SUCCESSIVE ROAD DESIGN ELEMENTS IN TWO-LANE RURAL HIGHWAYS

Transport ◽  
2015 ◽  
Vol 32 (2) ◽  
pp. 138-145 ◽  
Author(s):  
Laura Eboli ◽  
Giuseppe Guido ◽  
Gabriella Mazzulla ◽  
Giuseppe Pungillo
Keyword(s):  
Road Traffic ◽  
Characteristic Curve ◽  
Geometric Characteristic ◽  
Operating Speed ◽  
Rural Highways ◽  
Design Elements ◽  
Road Design ◽  
Long Time ◽  
Independent Variable ◽  
Design Consistency

Speed has been identified for a long time as a key risk factor in road traffic. Inappropriate speeds contribute to a relevant part of road crashes, and then to the mortality and disabilities resulting from them. Starting from this consideration this paper investigates road safety by analysing operating speed, which is the 85th percentile speed. Particularly, two regression models are proposed to predict operating speeds for different road elements related to specific road conditions. The case study is represented by a two-lane rural highway. Smartphone-equipped vehicles were used to evaluate the operating speed for each element of the analysed road segment. Continuous speed data were recorded by the vehicles driven by users with different driving behaviours. Since the lack of safety is often linked to an inconsistency roadway geometric design, we effected a preliminary quantitative design consistency evaluation that confirmed the need of having accurate experimental measures of operating speed or appropriate models for predicting it. We propose two types of operating speed models: one for estimating speed profiles for horizontal curves, and the other one for tangents. According to both models, operating speed is predicted by the combination of an independent variable representing a geometric characteristic (curve radius for the curves and length for the tangent elements) and an independent variable relating to the speed, and specifically the operating speed of the previous road element. The models show a good predictive capability, and can be considered as a useful tool for operators and technicians for road management.

scholarly journals Research of transient processes in case of single-phase insulation faults in low-voltage ship power grids, taking into account the resistance at the fault point

2020 ◽  
pp. 49-54
Author(s):  
И.Е. Кажекин
Keyword(s):  
Single Phase ◽  
Low Voltage ◽  
Experimental Studies ◽  
Power Grids ◽  
Transient Processes ◽  
Safety Issues ◽  
Physical Experiments ◽  
Marine Industry ◽  
Calculation Results ◽  
Constant Potential

В работе рассмотрены вопросы безопасности бортовых электросетей объектов морской индустрии, показано влияние перенапряжений на их основные показатели, которыми определяются опасности смертельных электротравм, опасности возникновения пожаров и взрывов. Представлены результаты математического моделирования электрического разряда по уравнению Майра с учетом особенностей переходного процесса при однофазных замыканиях на корпус. Показана роль напряжения смещения нейтрали по постоянному потенциалу, наибольшие значения которого формируются при неустойчивом контакте фазы с корпусом судна. Описаны результаты экспериментальных исследований переходных процессов, сопровождающихся возникновением неустойчивыми искровыми разрядами. Сравнение результатов расчета по предложенной методике с результатами физических экспериментов показало весьма удовлетворительную сходимость. Предложенная модель может быть использована для уточнения показателей, характеризующих безопасность судовых электросетей. The paper deals with the safety issues of on-board power grids of the marine industry facilities, shows the influence of overvoltages on their main indicators, which determine the dangers of fatal electrical injuries, the risk of fires and explosions. The results of mathematical modeling of an electric discharge according to the Mayr equation, taking into account the features of the transient process in single-phase short circuits to the case, are presented. The role of the bias voltage of the neutral at a constant potential is shown, the highest values ​​of which are formed during unstable contact of the phase with the ship's hull. The results of experimental studies of transient processes accompanied by the appearance of unstable spark discharges are described. Comparison of the calculation results by the proposed method with the results of physical experiments showed a very satisfactory convergence. The proposed model can be used to refine the indicators characterizing the safety of ship power grids.

scholarly journals The Concept of Development and Implementation of High-Speed Transport

2020 ◽  
Vol 18 (1) ◽  
pp. 58-72
Author(s):  
V. M. Alexeev ◽  
A. V. Vaganov ◽  
M. V. Katina
Keyword(s):  
High Speed ◽  
Magnetic Levitation ◽  
Transport Systems ◽  
Rolling Stock ◽  
Design Elements ◽  
Safety Issues ◽  
Current Collection ◽  
High Speeds ◽  
Technical Solutions ◽  
Original Approach

The article discusses the issues of implementation and organization of high-speed transport. The objective of the article is to consider possible options for implementing highspeed (HS) motion systems using the principle of magnetic levitation, which will ensure high speeds for delivery of goods and carrying people over long distances. To achieve this objective, it is necessary to develop an engine and technical solutions for design of HS rolling stock, make decisions on energy supply infrastructure and the HS track, address safety issues and new control systems considering the state of the infrastructure and its design elements. The article discusses several options for implementation of high-speed transport systems, differing in the power supply system, current collection and track based on the magnetic levitation approach. An original approach is proposed in implementation of magnetic levitation transport using the technology of electromagnetic guns designed to implement traction forces of a magnetic levitation vehicle. The advantage of this approach is that it opens the possibility of maneuvering for the vehicle while driving. This allows to abandon switch turnouts, now significantly limiting the use of magnetic levitation transport. A mathematical model describing interaction of an electromagnetic gun and supermagnets located on the track is considered. In constructing the model, methods of the theory of electromagnetic field and interaction of magnetic bodies were used, and when constructing a model of interaction of rolling stock with a magnetic track, methods of mathematical algebra and the Cauchy theorem were used. The article discusses various principles of organization of movement using the magnetic levitation for urban, suburban, and intercity transport.

Abstract 181: A Systematic Review of Interventions to Increase tPA Administration

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Mollie McDermott ◽  
Lesli E Skolarus ◽  
James F Burke
Keyword(s):  
Systematic Review ◽  
Public Education ◽  
Small Sample Size ◽  
Case Reports ◽  
Meta Analysis ◽  
Experimental Studies ◽  
Fixed Effect Model ◽  
Small Sample ◽  
Eligibility Criteria ◽  
Design Elements

Introduction: Rates of tPA administration remain low nationally and globally despite its demonstrated efficacy. We performed a systematic review and meta-analysis of interventions to increase the rate of tPA administration. Methods: We searched PubMed and EMBASE to identify all studies (excluding case reports) published between 1995 and January 8, 2015 documenting interventions to increase the utilization of tPA. We screened each study with pre-specified inclusion and exclusion criteria. Design elements and study data were extracted from eligible studies. The principal summary measure was the percentage change in rate of tPA administration. Fixed and random effects meta-analytic models were built to summarize the effect of intervention compared to control as well as intervention subtypes. Results: Our search yielded 1457 results of which 25 met eligibility criteria. We identified 13 pre-post studies and 11 randomized or quasi-experimental studies. Included studies utilized EMS (n=14), telemedicine (n=6), and public education (n=5). Intervention settings included urban (n=13), rural (n=4), and combined (n=4). In a fixed effect model, tPA administration was significantly higher in the intervention arm across all studies that limited enrollment to ischemic stroke patients (n=14) with a risk ratio (RR) of 1.71. Interventions involving EMS were associated with an increased rate of tPA administration with a RR of 1.51, (95% CI: 1.43-1.59, p<0.0001); promoting public education RR = 2.62, (95% CI: 1.54-4.43, p<0.01); and utilizing telemedicine RR = 2.97, (95% CI: 2.61-3.39, p<0.0001). Conclusions: Interventions to increase tPA use appear to have considerable efficacy. Comparative inferences between intervention types are limited by small sample size and intervention heterogeneity.

scholarly journals ACCEL: Spreadsheet-Based Cost Estimation for Forest Road Construction

2011 ◽  
Vol 26 (4) ◽  
pp. 189-197 ◽  
Author(s):  
Jarel C. Bruce ◽  
Han-Sup Han ◽  
Abdullah E. Akay ◽  
Woodam Chung
Keyword(s):  
Cost Estimation ◽  
Road Construction ◽  
Microsoft Excel ◽  
Diagram Method ◽  
Forest Road ◽  
Design Elements ◽  
Road Design ◽  
Visual Basic For Applications ◽  
Site Characteristics ◽  
Forest Road Construction

Abstract A computer program has been developed to aid forest engineers in the cost estimation of forest road construction activities. This new tool, called ACCEL, uses Visual Basic for Applications within Microsoft Excel to compute the costs of construction components using interactive sheets, automated tasks, and advanced computer routines. The user is guided through road construction components and prompted for cost data, earthwork quantities, survey information, and the conditions of the construction environment to estimate total construction cost. Road design elements and site characteristics are variables used to optimize earthwork allocation, improving on using the mass diagram method. The program also estimates clearing and grubbing areas, rock surfacing volumes, and culvert lengths. ACCEL was validated by comparing the results to those of RoadEng (by Softree), ensuring that formulas were input correctly and showing close agreement in results. This program was created in a recognizable format, i.e., Microsoft Excel, and builds on basic quantity and cost estimation techniques. ACCEL is intended to improve the decisionmaking process for experienced forestry practitioners in forest road construction regardless of region, company, or agency affiliation by accepting their inputs and performing the calculations for different route alternative or varying design specifications.

Safety Effects of Horizontal Curve Reliability Index

2020 ◽  
Vol 2674 (9) ◽  
pp. 627-636
Author(s):  
Scott Himes ◽  
Eric Donnell
Keyword(s):  
Reliability Index ◽  
Horizontal Curve ◽  
Mass Model ◽  
Crash Frequency ◽  
Horizontal Curves ◽  
Run Off ◽  
Single Vehicle ◽  
Green Book ◽  
Total Curve ◽  
The Relationship

Recent advancements in analytical processes have used probabilistic approaches to examine the efficacy of the point mass model (and other Green Book models) to develop reliability-based approaches for geometric design. However, there has been minimal research establishing the link between reliability measures and substantive safety (expressed through crash frequency). The objective of this paper is to use empirical data supporting the calculation of reliability index for existing horizontal curves and to estimate the relationship between reliability index and crash frequency. Other horizontal curve-related characteristics that may have an impact on crash frequency on horizontal curves for rural two-lane highways and rural freeway facilities are controlled for in the evaluation. The safety analysis showed that the wet pavement reliability index was significantly associated with crash frequency for total curve-related crashes, single-vehicle run-off-road crashes, rollover crashes, truck-related crashes, and weather-related crashes. The relationship was strongest for the reliability index in its continuous form, meaning that the effect is continuous across the range of wet pavement reliability that was observed.

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