Automatic identification of risky weather objects in line of flight (AIRWOLF)

Adverse weather conditions are hazardous to flight and contribute to re-routes and delays. This has a negative impact on the National Airspace System (NAS) due to reduced capacity and increased cost. In today’s air traffic control (ATC) system there is no automated weather information for air traffic management decision-support systems. There are also no automatic weather decision-support tools at the air traffic controller workstation. As a result, air traffic operators must integrate weather information and traffic information manually while making decisions. The vision in the Next Generation Air Transportation System (NextGen) includes new automation concepts with an integration of weather information and decision-making tools. Weather-sensitive traffic flow algorithms could automatically handle re-routes around weather affected areas; this would optimize the capacity during adverse conditions. In this paper, we outline a weather probe concept called automatic identification of risky weather objects in line of flight (AIRWOLF). The AIRWOLF operates in two steps: (a) derivation of polygons and weather objects from grid-based weather data and (b) subsequent identification of risky weather objects that conflict with an aircraft’s line of flight. We discuss how the AIRWOLF concept could increase capacity and safety while reducing pilot and air traffic operator workload. This could translate to reduced weather-related delays and reduced operating costs in the future NAS.     

Accident cost saving and highway attributes

Two semi-logarithmic regression models are developed to estimate accident rates and accident costs, respectively, for rural non-interstate highways in the state of Iowa. Data on 21,224 accidents occurring between 1989 and 1991 on 17,767 road segments are used in the analysis. Seven road attributes of these road segments are included as predictor variables. Applying the resulting regression models to a rather typical highway upgrade situation, the present value of the accident cost saving is computed. The sensitivity of the estimated cost saving to values for fatal, personal injury, and property damage only accidents is tested.Because factors other than road characteristics greatly influence accident costs, the models developed in this research explain a limited amount of the variance in these costs among road segments. Results of the analysis indicate that the most important attribute associated with accident costs is average daily traffic per lane, followed by conditions requiring passing restrictions and the sharpness of curves. Varying the values for the three categories of accidents shows that results are far more sensitive to the value of personal injuries than fatalities. The feasibility of using predictive models of accident costs in benefit-cost analyses of highway investments is demonstrated.     

The impact of climate change and weather on transport: An overview of empirical findings

This paper presents a survey of the empirical literature on the effects of climate change and weather conditions on the transport sector. Despite mixed evidence on many issues, several patterns can be observed. On a global scale especially shifts in tourism and agricultural production due to increased temperatures may lead to shifts in passenger and freight transport. The predicted rise in sea levels and the associated increase in frequency and intensity of storm surges and flooding incidences may furthermore be some of the most worrying consequences of climate change, especially for coastal areas. Climate change related shifts in weather patterns might also cause infrastructure disruptions. Clear patterns are that precipitation affects road safety by increasing accident frequency but decreasing severity. Precipitation also increases congestion, especially during peak hours. Furthermore, an increased frequency of low water levels may considerably increase costs of inland waterway transport. Despite these insights, the net impact of climate change on generalised costs of the various transport modes are uncertain and ambiguous, with a possible exception for inland waterway transport.     

Accident severity analysis using ordered probit model

To reduce injuries in road crashes, better understanding is needed between the relationship of injury severity and risk factors. This study seeks to identify the contributing factors affecting crash severity with broad considerations of driver characteristics, roadway features, vehicle types, pedestrian characteristics and crash characteristics using an ordered probit model. It also explores how the interaction of these factors will affect accident severity risk. Three types of accidents were investigated: two-vehicle crashes, single vehicle crashes and pedestrian accidents. The reported crash data in Singapore from 1992 to 2001 were used to illustrate the process of parameter estimation. Several factors such as vehicle type, road type, collision type, location type, pedestrian age, time of day of accident occurrence were found to be significantly associated with injury severity. It was also found that injury severity decreases over time for the three types of accident investigated.     

Bus accidents,bus deregulation and London

Local bus services were deregulated in October 1986 in all areas of Britain except London. Government policy is to extend deregulation to London, though not in the current parliament. This paper analyses statistics on bus accidents from the national road accident database from 1981 to 1991 to compare results for London and the rest of Great Britain, and to consider whether deregulation has affected safety. The conclusions depend on the assumption that accident recording practice was not itself affected by deregulation.Bus accident rates are higher in London than on built-up roads elsewhere, partly apparently because of road traffic conditions in London, and partly because open-platform buses have higher accident rates involving occupants, including boarding and alighting accidents, than buses with doors.The main safety effects of deregulation operate through its effects on bus activity, though there is also some evidence that the rate per bus-kilometre of accidents involving other road users fell slightly. This may be due in part to the trend towards smaller buses associated with deregulation. Deregulation has led to a fall in bus patronage, and thus to a fall in occupant casualties; and to a rise in bus-kilometres, and thus to a rise in casualties among other road users in accidents involving buses. The number of fatal and serious casualties among other road users involved in bus accidents is larger than the number among bus occupants, so deregulation in London could lead on balance to a small rise in fatalities involving buses. On the other hand, the number of slight casualties among other road users involved in bus accidents is smaller than the number among bus occupants, so deregulation in London could lead to a fall in the number of slight casualties involving buses.Although there were fears that changes in the management of bus operations or financial pressures might lead to increased accident rates following deregulation, there no evidence in the findings to support such fears.This paper was first presented at the 3rd International Conference on Competition and Ownership in Surface Public Transport at Mississauga, Canada on 25–29 September 1993. The author is grateful to the Department of Transport for the speed and efficiency with which they provided special tabulations from the road accident database for this study.     

驾驶人安全意识体验式训练装置研究

通过对目前常用驾驶人安全意识培训方法的对比,认为体验式培训为最适合的培训方法;进一步对我国2007-2010年间大型道路交通事故特征进行分析,得出驾乘人员不系安全带是引起人员伤亡一大原因。通过设计研发碰撞、翻转两个体验式训练装置,使驾乘人员在保证安全的前提下真切感受道路交通事故发生瞬间安全带对人体的保护作用,有效提高驾驶人的安全意识,减少道路交通事故的发生及人员的伤亡。     

Investigating effects of asphalt pavement conditions on traffic accidents in Tennessee based on the pavement management system (PMS)

Pavement maintenance is essential for ensuring good riding quality and avoiding traffic congestion, air pollution, and accidents. Improving road safety is one of the most important objectives for pavement management systems. This study utilized the Tennessee Pavement Management System (PMS) and Accident History Database (AHD) to investigate the relationship between accident frequency and pavement distress variables. Focusing on four urban interstates with asphalt pavements, divided median types, and 55 mph speed limits, 21 Negative Binomial Regression models were developed for predicting various types of traffic accident frequencies based on different pavement condition variables, including rut depth (RD), International Roughness Index (IRI), and Present Serviceability Index (PSI). The modeling results indicated that the RD models did not perform well, except for predicting accidents at night and accidents under rain weather conditions; whereas, IRI and PSI were always significant prediction variables in all types of accident models. Comparing the models goodness‐of‐fit results, it was found that the PSI models had a better performance in crash frequency prediction than the RD models and IRI models. This study suggests that the PSI accident prediction models should be considered as a comprehensive approach to integrate the highway safety factors into the pavement management system. Copyright © 2010 John Wiley & Sons, Ltd.     

道路交通事故发生机理与实例分析

交通事故发生机理是认识道路交通事故发生过程、交通事故预防和改善交通安全的基础。文章以道路交通系统为研究对象,分析道路交通事故的形成过程,将交通事故发生机理分为驾驶行为差错类事故发生机理、外部因素突变类事故发生机理、综合性事故发生机理三类,并在此基础上绘制了道路交通事故发生机理图,同时结合国道109线兰州八盘村路段进行了实例分析。     

Through the storm: Transit agency management in response to climate change

The increase in extreme weather events due to climate change poses serious challenges to public transit systems. These events disrupt transit operations, impair service quality, increase threats to public safety, and damage infrastructure. Despite the growing risk of extreme weather and climate change, little is known about how public managers recognize, experience and address these risks. Using data from a national study of public transit agencies we investigate the types of extreme weather events transit agencies are experiencing, the associated risks, and how agencies are preparing for them. We find that while extreme events are commonly experienced by transit agencies across states and transit managers perceive increased risks from these events, most agencies rely on the traditional emergency management approach to address extreme weather ex post rather than taking a proactive approach to mitigating the adverse weather impact on transit assets and infrastructure ex ante. Managers report that a lack of access to financial resources is the greatest challenge for undertaking adaptation and preparation. We conclude with a discussion of what these findings mean for understanding organizational adaptation behavior as well as climate adaptation policy making.     

Willingness-to-pay for road safety improvement

Few studies have explored, to date, the issue of the monetary valuation of non-fatal injuries caused by road traffic accidents. The present paper seeks to raise interest in this question and to estimate, by contingent valuation, French households’ willingness-to-pay (WTP) to improve their road safety level and reduce their risk of non-fatal injuries following a road accident. More precisely, a Tobit and a type-II Tobit model were estimated to identify factors for WTP. The results highlighted the significant positive influence of injury severity on WTP. Experience of road traffic accidents seemed to play an important role, positively influencing valuation of non-fatal injury.     

Impact assessment of extreme weather events on transport networks: A data-driven approach

The present paper presents a data-driven method for assessing the resilience of the European passenger transport network during extreme weather events. The method aims to fill in the gap of current research efforts regarding the quantification of impacts attributed to climate change and the identification of substitutability opportunities between transport modes in case of extreme weather events (EWE). The proposed method consists of three steps concerning the probability estimation of an EWE occurring within a transportation network, the assessment of its impacts and the passengers’ flow shift between various transport modes. A mathematical formulation for the proposed data-driven method is provided and applied in an indicative European small-scale network, in order to assess the impacts of EWE on modal choice. Results are expressed in passenger differentiated flows and the paper concludes with future research steps and directions.     

Winter problems on mountain passes – Implications for cost-benefit analysis

Cost-benefit analysis is a tool in government decision-making for determining the consequences of alternative uses of society’s scarce resources. Such a systematic process of comparing benefits and costs was adopted in early years for transportation projects and it has been the subject of much refining over the years. There are still some flaws, however, in the application of the method. In this article we have studied the impact of weather conditions on traffic speed on low traffic roads often exposed to adverse weather. This is an issue not currently considered in the cost-benefit analysis of road projects. By using two analytical approaches—structural equation modelling and classification and regression tree analysis—the impact of the weather indicators temperature, wind speed, and precipitation on traffic speed has been quantified. The data relates to three winter months on the European Route 6 road over the mountain pass Saltfjellet in Norway. Increase in wind speed, increase in precipitation and temperatures around freezing point all caused significant decrease in traffic speed in the case studied. If actions were taken to reduce the impact of adverse weather on traffic (e.g. by building a tunnel through the mountain) this study indicates that the road users would gain a total benefit of approximately 2,348,000 NOK (282,000 EUR) each winter at Saltfjellet if all the weather related benefits were included. We argue that this is a significant number that is highly relevant to include in CBAs. This applies both to the CBAs of new transportation projects as well as when resources are allocated for operation, maintenance, and monitoring of the existing transport systems. Including the weather related benefits would improve the application of CBA as a decision-making tool for policy makers.     

基于关联规则的重大道路交通事故影响因素分析

相比于一般交通事故,重大道路交通事故的特征及其影响机理会有所差异,本文旨在研究重大道路交通事故的分布特征及其主要影响因素。收集2014至2018年的重大道路交通事故数据,从驾驶员行为、车辆状况、道路线形和时空分布方面对重大道路交通事故的基本特征进行分析,采用关联规则技术深入挖掘重大道路交通事故多因素的影响机理。从人、车、道路和环境四个方面,重点讨论了重大道路交通事故中的两因素和三因素交互作用的影响机理,并据此提出了针对性的事故预防措施。     

Implications of climate change for thermal discomfort on underground railways

Hot weather events, ventilation assets, changing passenger demand and service expectations have all caused increased attention on thermal comfort on London’s Tube. This study provides estimates of the future number of days when passengers travelling on sections of the Tube could be subjected to thermal discomfort under future scenarios of climate change, and the potential number of passengers dissatisfied. A risk based methodology is presented, integrating a spatial weather generator modified for urban areas and a thermal comfort model. The study provides an initial assessment of adaptation options by considering the implications of lowering train temperatures by 2 °C and 4 °C to represent saloon cooling. Median results under a 2050 high scenario indicate that all Tube lines assessed could experience near-complete passenger dissatisfaction with the thermal environment in trains in the unlikely event that nothing else were to change. Adaptation aimed at lowering train temperatures has the potential to provide tangible improvements in thermal comfort. However, this was not projected to be sufficient to maintain comfortable thermal conditions for many of the lines in the 2050s under high emission scenarios, requiring a combination of other infrastructure cooling measures to be implemented in parallel.     

A Methodology for estimating traffic safety improvements at intersections

Intersection accidents represent a significant proportion of overall motor vehicle accidents. More accurate estimates of the actual effectiveness of intersection safety improvements are required. This study develops an improved methodology for post-implementation evaluation of safety countermeasures at intersections. Accidents are random, rarely occurring events. For a given time period, this leads to random fluctuations in accident frequencies, which suggests that statistical analysis employing confidence intervals, rather than point estimates, is required. Two technical problems complicate this treatment of accident occurrence as a random variable. The first problem is that identifying of hazardous locations is generally based on above-average accident frequency during the most recent period(s) for which data is available. The second problem arises from changes in external factors such as traffic volume, motor vehicle safety standards, etc., during the period of analysis, which may also affect traffic safety. A “combined” approach which addresses these technical issues is developed. Empirical Bayesian methodology is combined with regression techniques to derive a more accurate measure of the effect of safety treatments. An important consideration is the derivation of the variance of this measure, so that appropriate confidence intervals may be constructed. The approach is then applied to a sample of locations that underwent treatment by the Massachusetts Department of Public Works (MDPW). We compare our results to those which might be obtained using alternative methodologies that correct for neither or only one of the technical problems. We also illustrate how preliminary conclusions may be drawn regarding the effectiveness of broad categories of treatments, and how individual sites requiring further investigation may be identified.     

Transportation Risk ANalysis tool for hazardous Substances (TRANS) – A user-friendly,semi-quantitative multi-mode hazmat transport route safety risk estimation methodology for Flanders

The paper develops a methodology for assessing the relative risk levels in moving hazardous materials by various transport modes. Transportation Risk ANalysis tool for hazardous Substances (TRANS) divides routes into smaller segments using multi-criteria analysis and likelihood scores of accidents in which dangerous cargoes are involved possibly causing fatalities. The consequences of accident scenarios are calculated in terms of the number of people within 1% of the lethal distance from the accident centre. This provides a user-friendly, semi-quantitative risk analysis tool. The generic method allows for comparing the risk levels of the segments of routes used in the transportation of hazardous goods.     

Effect of climate change on asphalt binder selection for road construction in Italy

This work explores the influence of climate changes on the proper selection of asphalt binder for pavement construction purposes, according to the Performance Grade (PG) defined in the SUPERPAVE specifications. Based on temperature data at national level, it is possible to obtain thematic maps for the whole Italian territory, which is extremely useful for technicians and pavement engineers for selection of asphalt binder for road construction purposes. Furthermore, the statistical significant temperature trends’ knowledge enables deriving thematic maps which allows to include the effects of climate change in the asphalt binder design. It is argued that, due to climate change, the binders to be selected may be different from those commonly selected at the design stage of the infrastructure, since likely higher temperature determine more demanding constraints. The comparison among the PG grades necessary for covering the needs for construction in the different regions of Italy also call for highly performing binders, such as those obtained via specific modification with polymers. This will also imply the need for even more performing materials, in terms of mechanical properties and durability, to be used for modification of neat asphalt as well as the need for defining new specification and testing methods, specifically valid for these modified materials.     

Climate change impacts on transport on the Rhine and Danube: A multimodal approach

This paper measures the potential effects of low water levels on the Rhine and Danube navigation in the context of weather variability and a number of climate change scenarios. A long-term multimodal network transport analysis over the period 2005–2050 is presented; it analyzes the impact of changes on the water depth conditions on transport costs and the modal splits between three competing modes. The results indicate that the impact of climate change until 2050 should be limited.     

Updating predictive accident models of modern rural single carriageway A-roads

Abstract

Reliable predictive accident models (PAMs) are essential to design and maintain safe road networks, and yet the models most commonly used in the UK were derived using data collected 20 to 30 years ago. Given that the national personal injury accident total fell by some 30% in the last 25 years, while road traffic increased by over 60%, significant errors in scheme appraisal and evaluation based on the models currently in use seem inevitable. In this paper, the temporal transferability of PAMs for modern rural single carriageway A-roads is investigated, and their predictive performance is evaluated against a recent data set. Despite the age of these models, the PAMs for predicting the total accidents provide a remarkably good fit to recent data and these are more accurate than models where accidents are disaggregated by type. The performance of the models can be improved by calibrating them against recent data.     

An application of the directional distance function with the number of accidents as an undesirable output to measure the technical efficiency of state road transport in India

By using the directional distance function (DDF) of data envelopment analysis (DEA), this study measures the technical efficiency of 37 Indian state road transport undertakings (SRTUs) for the year 2012–13. We employ the DDF as a tool for analyzing a joint production function with both desirable and undesirable outputs (i.e., the number of accidents). A comparison between the results with and without accidents shows that several SRTUs have experienced significant changes in their efficiency scores as well as in their rankings after accounting for the undesirable output. This indicates the importance of including the number of accidents – a safety standard – as representative of the undesirable output in computing the efficiency scores of SRTUs. The results of the Tobit model indicate that SRTUs with greater vehicle productivity are more efficient under both conventional DEA and DDF approaches. We also employed zero-truncated negative binomial model to assess the factors influencing the number of road accident experienced by the Indian SRTUs and found that the accident count was significantly influenced by fleet utilization and vehicle productivity.