Sökresultat

Filtyp

Din sökning på "*" gav 536924 sökträffar

Investigating the influence of segmentation in estimating safety performance functions for roadway sections

Safety performance functions (SPFs) are crucial to science-based road safety management. Success in developing and applying SPFs, apart data quality and availability, depends fundamentally on two key factors: the validity of the statistical inferences for the available data and on how well the data can be organized into distinct homogeneous entities. The latter aspect plays a key role in the ident

Safety assessment of passing relief lanes using microsimulation-based conflicts analysis

The paper target is to analyze the influence of passing lane section and merging area lengths, which represent a critical part in the geometric design of passing lanes. The lack of observed data and the still limited implementation of short passing 2 + 1 lane in Poland do not allow to perform a reliable performance-based design of their length to balance context and economical restrains with opera

Monitoring of railway track with light high efficiency systems

Rail Track performance is highly dependent upon the magnitude and variation of differential track geometry. Consequently, there is an increasing interest in obtaining a consistent measure of trackbed stiffness and track geometry in the physical and time restrictions applicable on live track for assessing potential maintenance requirement and subsequent design of remedial measures. Furthermore, a l

Application of an intelligent transportation system in a travel time information system : Safety assessment and management

The research presented here evaluated road safety on the road sections included in the Intelligent Traffic Control System of the Podhale Region (ISSRRP) in Poland. This travel time information system consists of a remote traffic microwave sensor, cameras, as well as automatic plate number recognition on national roads with variable message signs and a mobile app to suggest alternative routes in th

Evaluating the safety benefit of retrofitting motorways section with barriers meeting a new EU standard : Comparison of observational before–after methodologies

The road safety barriers are today designed and installed in compliance with the European standards for Road Restraint Systems (EN 1317), which lays down common requirements for the testing and certification in all EU countries. The introduction of the European Union (EU) regulation for safety barriers, which is based on performance, has encouraged European road agencies to perform an upgrade of t

From manual to automatic pavement distress detection and classification

Detection and classification of distresses is a fundamental activity in the road pavement management. Even in the early stages of deterioration, road pavement needs to be monitored to identify problems, evaluating the actual conditions and predicting what the future conditions will be. Monitoring activities through manual/visual inspections are time consuming, costly and cause of safety concerns.

No title

The European Directive 2008/96/CE on Road Infrastructures Safety Management gives great emphasis to road Safety Inspections SI as tool for safety management of existing roads. In this framework, development of surrogate measures of safety derived from data collected during safety inspections can provide a source of information for risk assessment. Furthermore, SIs derived information seems to be p

Investigating the influence of passing relief lane sections on safety and traffic performance

As it is well known, one of the keys to improve traffic performance of two lane rural roads with high traffic volumes is to provide passing sections. However, providing a long segment in which the passing maneuver is allowed, is not always feasible, especially when suburban areas are considered. The retrofitting of some road sections by adding a passing relief lane can improve traffic performance

Investigating the influence on safety of retrofitting Italian motorways with barriers meeting a new EU standard

Objective: A new European Union (EU) regulation for safety barriers, which is based on performance, has encouraged road agencies to perform an upgrade of old barriers, with the expectation that there will be safety benefits at the retrofitted sites. The new class of barriers was designed and installed in compliance with the 1998 (European Norm) EN 1317 standards for road restraint systems, which l

Comparison of Italian and Hungarian Black Spot Ranking

Black spot ranking is an important tool for finding the sites with potential safety improvement on the road network. The EU Directive on Road Infrastructure Safety Management also demands the ranking of high accident concentration sites. This paper gives an introduction to localizing high accident concentration sites and the indicators used by Italy and Hungary. Accident and traffic volume data ar

The assessment of road safety for passing relief lanes using microsimulation and traffic conflict analysis

Most crash prediction models are statistically-based prediction methods which require significant efforts in crash data collection and may not be applied in particular traffic environments due to the limitation of data sources. Traffic conflict studies have been proposed to mitigate this issue using short time survey to count traffic conflicts which are assumed as a surrogate measure of safety. Un

Comparison of in situ devices for the assessment of pavement subgrade stiffness

The subgrade is the top surface of a roadbed upon which the pavement structure is constructed. The purpose is to provide a platform for construction of the pavement and to support the pavement without unwanted deflection that would reduce its performance. For those reasons subgrade bearing capacity have to be investigate during the construction process as a quality control, based on the design res

Assessing the stochastic variability of the Benefit-Cost ratio in roadway safety management

Road Agencies set quantitative targets and adopt related road safety strategies within the priorities and the available resources at the time of an economic crisis. In this framework, benefit-cost analyses (BCA) are carried out to support the decision making process and alternative measures are ranked according to their expected benefit and benefit-cost ratio calculated using a Safety Performance

Reliability-based assessment of benefits in roadway safety management

Road agencies set quantitative targets and adopt related road safety strategics in accordance with each agency's priorities and available resources. Benefit-cost analyses are carried out to support the decision-making process, and alternative measures are ranked according to their expected benefits and benefit-cost ratios, calculated with a safety performance function (SPF) and crash modification

Investigating transferability and goodness of fit of two different approaches of segmentation and model form for estimating safety performance of motorways

The analysis of a road network could be carried out using different techniques, the most advanced of which for the identification of hazardous sites are based on a statistical tool known as a "Safety Performance Function" (SPF). SPFs are fundamental to procedures in the Highway Safety Manual (HSM) and Safety Analyst, both of which require calibration of the SPFs to local conditions. In the case of

Dread and Risk Elimination Premium for the Value of a Statistical Life

The value of a statistical life (VSL) is a widely used measure for the value of mortality risk reduction. As VSL should reflect preferences and attitudes to risk, there are reasons to believe that it varies depending on the type of risk involved. It has been argued that cancer should be considered a "dread disease," which supports the use of a "cancer premium." The objective of this study is to in

DMAC: Deadline-Miss-Aware Control

The real-time implementation of periodic controllers requires solving a co-design problem, in which the choice of the controller sampling period is a crucial element. Classic design techniques limit the period exploration to safe values, that guarantee the correct execution of the controller alongside the remaining real-time load, i.e., ensuring that the controller worst-case response time does no

A functional agonist of insect olfactory receptors : Behavior, physiology and structure

Chemical signaling is ubiquitous and employs a variety of receptor types to detect the cacophony of molecules relevant for each living organism. Insects, our most diverse taxon, have evolved unique olfactory receptors with as little as 10% sequence identity between receptor types. We have identified a promiscuous volatile, 2-methyltetrahydro-3-furanone (coffee furanone), that elicits chemosensory