The vulnerability of the environment to spills of dangerous substances on highways: A diagnosis based on multi criteria modeling

Highways and freeways are the main infrastructure channel used to transport cargo in Brazil. This cargo often includes dangerous chemical products which can, in the event of an accident, negatively impact the environment. The development and implementation of tools for the rapid diagnosis of environmental vulnerability in the transportation of dangerous goods has been studied. However, for highways and freeways there is a lack of studies based on environmental attributes, and not just based on statistical data which demands a specific period for collection and analysis and only after that the implementation of preventive measures. Thus, evaluation grounded on multiple criteria embedded in Geographic Information System (GIS) has significant potential for the practical implementation of risk management of road transportation of dangerous goods. This study has determined the environmental vulnerability of route BR 050, specifically the segment between the cities of Uberlândia and Uberaba in the state of Minas Gerais, where multi criteria analysis has been efficient in determining the most vulnerable areas. The main attributes analyzed were the drainage density, soil type and geology, determining that in case of an accident with dangerous substances the regional environment would be immediately affected, and so endorsing the use of this tool in many segments involved in environmental management of highway enterprises.     

Measuring post-disaster transportation system performance: the 1995 Kobe earthquake in comparative perspective

Recent earthquake disasters have caused major damage to transportation networks, leading to significant economic disruption. While this suggests the need to evaluate total system performance in transportation risk assessment, in addition to examining the vulnerability of individual components such as bridges, no appropriate measures currently exist. This paper develops post-disaster system performance measures and applies them to the urban rail and highway transportation systems in the Kobe, Japan, region devastated by the 1995 Hyogoken–Nanbu earthquake. Performance is evaluated in terms of network coverage and transport accessibility. Performance degradation was much more severe for highways and railways than for other lifeline infrastructure systems. Both transportation systems fared poorly in the disaster but service restoration proceeded much more rapidly for rail. The restoration of highway system performance correlated closely with the recovery of highway traffic volumes. The paper further develops a measure of subarea transport accessibility and applies this to Kobe’s constituent city wards. Results indicate substantial spatial disparity that is maintained throughout the restoration period. Comparisons with the 1989 Loma Prieta and 1994 Northridge earthquakes in the US show that although these disasters caused notable damage to highway bridges, system performance degradation was small in comparison with the Kobe experience. The paper argues that explicitly measuring transportation system performance can greatly facilitate both understanding the effects of historic disasters and preparing for future hazard events.     

Revisiting the notion of induced traffic through a matched-pairs study

In investigating the question of the existence of "induced demand" in connection with highway expansion projects, Hansen et al. (1993) studied eighteen California state highway segments whose capacities had been improved in the early 1970s. For the present study, these segments were paired with control segments that matched the improved segments to unimproved ones with regard to facility type, region, approximate size, and initial volumes and congestion levels. Taking annual data for average daily traffic (ADT) and design-hour-traffic-to-capacity (DTC) ratios during the 21 years 1976–1996, three approaches were used to compare growth rates between the improved and unimproved segments: overall growth comparisons for the matched pairs, repeated measures analysis, and analysis of matched mean profiles. We found the growth rates between the two types of segments to be statistically and practically indistinguishable, suggesting that the capacity expansions, in and of themselves, had a negligible effect on traffic growth over the period studied. Reasons for the differences between these results and those of aggregate cross-sectional models finding a significant induced demand effect are discussed. Our analyses suggest that the aggregate models may overestimate induced traffic due to the attribution of at least a fraction of the observed traffic growth to "induced demand" rather than to some of the confounding factors which were not controlled for in such studies. At the same time, it is noted that the traffic induced by capacity expansion may in certain circumstances be larger than that observed in the present study, with the effect of new highway construction on traffic growth being a prime candidate for scrutiny in this regard. The results of this study nonetheless suggest that, for existing facilities, the size of the induced-traffic effect that can be attributed to capacity enhancements may be sufficiently small that its detection in a case-control study would be difficult, if not impossible, without a substantially larger sample size.     

Design and evaluation of an automated highway system with optimized lane assignment

Highway automation entails the application of control, sensing and communication technologies to road vehicles, with the objective of improving highway performance. It has been envisioned that automation could increase highway capacity by a factor of three. The purpose of this paper is to develop a methodology for predicting highway capacity and comparing alternative automation concepts. It extends earlier research on optimal lane assignment on an automated highway to dynamic networks. A path-based linear program is formulated and solved through a column generation method. The algorithm has been applied to networks with as many as 20 on and off ramps, 80 segments, 4 lanes and 12 time periods.     

Evaluating speed consistency between successive elements of a two-lane rural highway

The V₈₅ speed reflects the 85th percentile speed of vehicles in a traffic stream passing a given element on the highway section. The large amount of speed differential in V₈₅ between the two successive elements along a highway reflects lack of speed consistency in the highway section. This lack of speed consistency can result in increased crash risk. Recent research points to several problems associated with the conventional method of measuring ΔV₈₅ between successive highway elements: (1) failure to reflect individual vehicle speed profiles; and (2) failure to account for inter-dependence in individual vehicle speeds between successive elements. These problems have serious implications for justifying safety treatment when conventional ΔV₈₅ measure is applied. A number of researchers have suggested that the estimated speed differential based on individual vehicle speed profiles in successive elements is significantly higher than that obtained using the conventional approach. In this paper, we assess the safety implications of using the conventional ΔV₈₅ and introduce a hierarchical model for considering individual vehicles speed consistency. These findings lead to important implications for introducing engineering treatments to improve safety along in two-lane rural highways based on the criteria of speed consistency.     

公路项目穿越饮用水水源保护区的环境风险防范措施探讨

环境风险是涉及饮用水水源保护区的公路项目营运期最主要的环境问题。文章从竣工环保验收实践角度,总结了广西公路项目穿越饮用水水源保护区的环境风险防范中存在的主要问题,并提出了相应的设计优化建议和对策,旨在为妥善解决公路建设与饮用水源保护间突出矛盾提供技术支持,为公路建设、设计单位等有关单位防范环境风险提供技术参考。     

Multiple criteria evaluation of transportation system improvement projects: The case of korea

As a newly industrialized country, Korea has shown remarkable economic progress in the last three decades. This phenomenal growth has rapidly increased demands for better quality of life. This includes, among others, increasing demand for high quality transportation system services. In this paper, the method of Analytic Hierarchy Process (AHP) is utilized to evaluate rural highway improvement projects in Korea. The appropriate rural highway improvement projects for widening and paving were selected and studied on the basis of some selection criteria. The results have shown that there are some significant differences in prioritizing projects using the traditional economic evaluation method as compared to those resulting from the use of AHP. As demonstrated, the AHP proves to be an effective tool in evaluating transportation system projects.     

双车道公路盾构隧道管片合理分块型式研究

文章以双车道公路盾构隧道为例,设计了三种不同分块型式的管片结构,并采用梁-弹簧模型模拟装配式管片结构,借助于有限元法分析了在不同拼装方式下管片结构的力学特性;通过对内力和变形的分析比较,并综合考虑设计、施工及其造价等因素,认为在最不利荷载作用下的管片结构宜采用10块分块型式;管片结构的正负弯矩值相差很大,故宜将内外两侧的钢筋分开进行配筋设计。     

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.     

Impact of horizontal geometric design of two-lane rural roads on vehicle co2 emissions

In 2014, highway vehicles accounted for 72.8% of all Greenhouse Gases emissions from transportation in Europe. In the United States (US), emissions follow a similar trend. Although many initiatives try to mitigate emissions by focusing on traffic operations, little is known about the relationship between emissions and road design. It is feasible that some designs may increase average flow speed and reduce accelerations, consequently minimizing emissions.This study aims to evaluate the impact of road horizontal alignment on CO₂ emissions produced by passenger cars using a new methodology based on naturalistic data collection. Individual continuous speed profiles were collected from actual drivers along eleven two-lane rural road sections that were divided into 29 homogeneous road segments. The CO₂ emission rate for each homogeneous road segment was estimated as the average of CO₂ emission rates of all vehicles driving, estimated by applying the VT-Micro model.The analysis concluded that CO₂ emission rates increase with the Curvature Change Rate. Smooth road segments normally allowed drivers to reach higher speeds and maintain them with fewer accelerations. Additionally, smother segments required less time to cover the same distance, so emissions per length were lower. It was also observed that low mean speeds produce high CO₂ emission rates and they increase even more on roads with high speed dispersions.Based on this data, several regression models were calibrated for different vehicle types to estimate CO₂ emissions on a specific road segment. These results could be used to incorporate sustainability principles to highway geometric design.     

Highway drivers' willingness to pay for speeding violations in Taiwan

This study investigates the effects of various factors on highway drivers' speeding behaviour and estimates the amount of money that a highway driver is willing to pay for speeding violations in Taiwan. The contingent valuation method is applied to measure drivers' preference and to derive the value function of the amount of money. Logit and probit models are estimated to analyse the significant variables influencing speeding behaviour and to calculate the willingness to pay for speeding violations. The research results show that increasing speeding fines is an effective way to reduce illegal driving behaviour on highways. Significant variables affecting highway drivers' speeding behaviour include gender, engine capacity, past offenders in the previous year, and the risk‐seeking characteristics of drivers. Finally, the logit and probit models show that the amounts of money that highway drivers are willing to pay for speeding violations are $US119 and $US116, respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

高速公路建设期重大危险源辨识探讨

文章基于危险源及重大危险源的一般定义,结合湖北杭瑞高速公路建设的实际情况,提出了高速公路建设期重大危险源的定义,并通过建立概率风险评价分析模型,采用事故树分析法和德尔菲法确定了事故发生的概率值,得出了判别重大危险源的风险度临界值,以对类似高速公路建设期重大危险源的辨识提供指导。     

Evaluating the significance of highway network links under the flood damage: An accessibility approach

This paper conducts an analysis to assess the significance of highway network links in Maryland under flood damage. An accessibility index is derived to incorporate the distance-decay effect and the volume of traffic influence on the transportation network. The accessibility level of individual counties and the state as a whole is checked before and after the hypothetical disruption of individual links within the floodplain. The results indicate that critical links identified based on the distance-only and the distance-traffic volume criteria appear to be different, implying that the priority of retrofit might also vary depending on what criterion to choose. The percentage loss of accessibility due to the disruption of a link is generally greater in the latter. However, distance-only consideration results in a more prominent spatial distribution pattern of links in percentage loss induced. Some links remain significant in both cases. Especially if the disruption of a certain link does not have an alternative solution (for example, if the link is the only way in and out of a certain county) and if counties connected by the link are low accessibility counties, the two criteria may produce a similar outcome.     

新农村建设背景下加快广西农村公路发展对策探讨

文章基于农村公路建设在社会主义新农村建设中的重要性,分析了广西农村公路建设发展中存在的问题,提出了加快广西农村公路发展的相关对策,以期不断提高广西农村公路建设和管理的水平.     

山区公路长大下坡路段安全隐患整治技术探讨

文章介绍了山区公路危险路段(点)的鉴别方法,提出了山区公路长大下坡路段安全隐患整治的方法和措施,并结合云南省某高速公路进行了安全隐患整治实例验证。结果表明,该整治技术有效可行,能够改善山区公路长大下坡危险路段(点)车辆运行速度的协调性和降低车辆出现制动失效的可能性。     

Considering the financial ratios on the performance evaluation of highway bus industry

This paper tries to construct a performance evaluation procedure for highway buses with the financial ratio taken into consideration. First, a conceptual framework is redeveloped, based on the one created by Fielding et al ., to help form evaluation items and performance indicators involving both transport and finance aspects. Second, the total performance is divided into three major kinds of efficiency?production, marketing, execution?according to the cycle of operation activities. Third, to overcome the problems of small sample size and unknown distribution of samples, the grey relation analysis is used to select the representative indicators, and the TOPSIS method is used for the outranking of highway bus. In addition, a case study is conducted using four highway bus companies as example. The empirical result shows that the performance evaluation for highway buses could become more comprehensive if financial ratios are considered.     

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.     

Residential moving intentions at highway locations: The trade-off between nuisances and accessibility in the Netherlands

This study investigates how highway nuisances are traded off against accessibility gains and other residential characteristics in the moving intentions of people living near highways. It studies a potential mediating role for residential satisfaction and potential mitigating relationships with highway nuisance perceptions. Structural Equation Modelling was used to test a proposed framework based on survey data collected from 1220 respondents living within 1000 m from a highway in the Netherlands.The results show that higher levels of perceived highway nuisances are associated with increased intentions to move, mediated by lower residential satisfaction. However, better perceived accessibility was not associated with either lower moving intentions or lower highway nuisance perception. Highway usage/interest and other residential characteristics – such as satisfaction with buildings, traffic safety, and amount of greenery – seem to countervail perceived highway nuisances as they reduce moving intentions and reduce highway nuisance perception. Finally, the results show that some groups – for example home owners – were less inclined to move (direct effect), independently of their residential satisfaction.From a practical perspective, a more inclusive perspective on highway planning, which accounts for accessibility and other residential characteristics as potential compensators and mitigators for highway nuisances, would be effective to reduce residential stress which could prevent protest and consequent cost overruns of projects.     

Unbalanced development of inter-provincial high-grade highway in China: Decomposing the Gini coefficient

This study discusses the unbalanced development of Chinese inter-provincial high-grade highway from 1997 to 2013. It does so from the viewpoint of the inter-provincial Gini coefficient based on per capita mileage of high-grade highway, which is decomposed according to such dimensions as the increment of the Gini coefficient, the Gini coefficient of different types of high-grade highway, and the Gini coefficient between and within inland and coastal areas. The Gini coefficient of China’s per capita mileage of inter-provincial high-grade highway shows a declining trend year by year. According to the results from the decomposition of the contribution rate of different types of high-grade highway, the unbalanced development of inter-provincial high-grade highway is caused mainly by that of first- and second-grade highway. According to the results from the decomposition related to the increment of the Gini coefficient of China’s per capita mileage of inter-provincial high-grade highway, the decrease of the Gini coefficient from 1997 to 2013 was mainly the result of balanced distribution of high-grade highway among regions in China. According to the results from the decomposition of the Gini coefficient between and within inland and coastal areas, the unbalanced development of inter-provincial high-grade highway in China from 1997 to 2013 was caused mainly by the unbalanced development of inter-provincial high-grade highway in inland areas. Therefore, the authors argue that the government should pay more attention to protecting the environment and providing a suitable scale of highway network, which could promote long-term sustainable development.     

公路施工企业现金流的风险与防范

文章通过对公路施工企业容易出现的现金流风险种类及成因进行分析,提出了一些有效的现金流风险防范措施,避免企业出现现金流风险而导致破产。