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1.
The traditional model for mitigating a transportation project’s environmental impacts typically operates project-by-project and delivers the mitigation just-in-time. In contrast, the newer practice of advance mitigation comprehensively assesses and mitigates impacts from one or multiple transportation projects before or during project planning, sometimes long before project construction begins. The practice has gained adherents for its potential to improve ecological outcomes, by better aligning mitigation and conservation goals. Advance mitigation also stands to reduce mitigation costs, an important secondary benefit for transportation agencies with constrained resources. Evidence of cost savings, however, has been piecemeal and anecdotal. This paper advances knowledge of advance mitigation’s financial impacts in two ways. First, it critically assesses the evidence about cost savings realized through advance mitigation, both through avoided up-front costs and reduced project delay. Second, it directly estimates the project time savings that might accrue with advance mitigation of state highway projects in California. Overall, the balance of evidence is encouraging for transportation agencies that would introduce the practice, and general agreement exists on its financial benefits. Considering project delays related only to the environmental process, we estimate advance mitigation could reduce delivery times by 1.3–5.0 months per project. Still, we also identify factors limiting comprehensive analysis. Transportation agencies adopting advance mitigation practices into their operations could use a pilot approach that includes rigorous environmental and mitigation cost accounting; such pilots would build needed empirical evidence of advance mitigation’s financial and ecological outcomes.  相似文献   

2.
Although governments often respond to the prevalent cost overruns of transportation projects by reforming the agencies charged with overseeing the construction of projects, the transportation research literature has not provided statistical evidence as to whether such reforms assist in reducing cost overruns. This paper provides such evidence using the Norwegian road sector as a case study. The agency in question was reformed twice, from a monopolistic to a semi-monopolistic organization, and finally, to a fully competitive organization in which road construction was divided out into a separate company and privatized. In this work, we use statistical inferences to explore the related issues. The data set is composed of 1045 projects evenly distributed across the three organizational forms. The results demonstrate that the impact of the reforms has not been equal. The most important impact occurred in the final reform of full competition in which both the cost overruns and delays in construction among larger projects were greatly reduced. The second reform appears to have had a contrasting impact. For transportation research in general, we call for additional studies that will reveal the extent to which efforts carried out by governments (such as reforms) improve the efficiency of these sectors.  相似文献   

3.
Contracted service comprises a significant proportion of total operating expenses in the provision of fixed-route bus transit service in the US. Despite its importance, the literature on the economic effects of transit service contracting has been limited to only a few studies since the mid-1990s, and is inconclusive due to problems with the nature and methodology of the past studies.This paper examines how the cost efficiency of providing fixed-route bus transit service varies by the degree of contracting. I make several improvements to previous studies and conduct a regression analysis that: (1) addresses the endogeneity problem between the contracting decision and cost efficiency, (2) differentiates between agencies that contract out only a portion of service from those that contract out all service, (3) takes into account the moderating effects of several factors on the effect of contracting on cost efficiency, and (4) uses a relatively larger set of cross-sectional time-series data constructed from the National Transit Database from 1992 to 2000.The analysis results show that the combined effects of contracting lower operating costs by $4.09 and $2.89 per vehicle hour for partial and full-contracting agencies, respectively, in the average case. These average cost savings translate into 7.8% and 5.5%, using the average operating cost per vehicle hour of $53.06. However, this improvement is not universal, because the effects of contracting on cost efficiency vary by factors such as peak-to-base ratio, agency size, the wage gap between bus operators in the public and private sectors, and agency type.  相似文献   

4.
In current practice, very few Metropolitan Planning Agencies attempt to capture the effects of transportation system changes on land use, and the consequent feedback effects on transportation system performance, despite substantial evidence that these effects may be significant. In this paper, we present a case study on the application of UrbanSim, a detailed land use simulation model system, and its integration with a regional travel demand model in the Greater Wasatch Front area of Utah. Like several other metropolitan areas, this region has recently been confronted with legal challenges to proposed highway projects, drawing substantial scrutiny to the land use-transportation connection. We describe the UrbanSim model specification, results from model estimation, and sensitivity analyses conducted with the combined land use and travel model system. The results of the sensitivity analysis suggest that accounting for the land use effects of a regional transportation plan may produce significant shifts in key transportation evaluation measures such as vehicle miles traveled, vehicle hours traveled, and hours of congestion delay.  相似文献   

5.
Rivers and streams worldwide are highly fragmented by dams and road crossings, and there is a pressing need to retrofit the most problematic structures to ensure aquatic organism passage. At the same time, a majority of the transportation infrastructure within developed nations is beyond its projected lifespan and significant investments will be needed to ensure that this transportation infrastructure remains safe and functional. Historically, these two problems have been addressed separately. Here, we use a rapid survey methodology to identify road-stream crossings that are likely high-priority projects for both conservation and infrastructure agencies. We conducted a field assessment of more than 700 road-stream crossings across Oklahoma to determine if they blocked fish movements and to determine their physical condition. We then developed an index of ecological impact, and an index of infrastructure condition, based on physical variables measured at each crossing. This survey revealed a subset of crossings that are both fragmenting the river network and in poor physical condition. These crossings are high-priority locations where culvert replacement may have both high ecosystem benefit and would eliminate a piece of transportation infrastructure with a high risk of failure. We discuss opportunities for cost-sharing between conservation and transportation agencies.  相似文献   

6.
Industrialized countries have extensive experience with various transportation energy conservation measures and have been making steady progress in improving the efficiency of their transport sector. Less Developed Countries (LDCs) have also been making progress, but their experience in many aspects of transportation energy conservation is very limited. Development organizations have funded many transportation projects in developing countries, but the vast majority of these projects were designed to improve the transportation infrastructure. Very few transportation energy conservation projects have been implemented and decision-makers face a scarcity of information on effective strategies. This paper gives an overview of transportation projects in LDCs in order to identify those transportation energy conservation measures that offer the greatest potential for LDCs. Two case studies, from Tunisia and Costa Rica, are given to illustrate the issues involved in implementing transportation energy conservation measures in LDCs. Conclusions are drawn to suggest actions for developing countries and for development organizations.Acronyms DECAT Driver Energy Conservation Awareness Training - DSE Direccion Sectorial de Energia (Costa Rica) - GDP Gross domestic product - km Kilometer - LDCs Less Developed Countries - TOE Metric tonne of oil equivalent - USAID US Agency for International Development  相似文献   

7.
A rising trend in state and federal transportation finance is to invest capital dollars into projects which reduce greenhouse gas (GHG) emissions. However, a key metric for comparing projects, the cost-effectiveness of GHG emissions reductions, is highly dependent on the cost-benefit methodology employed in the analysis. Our analysis comparing California High-Speed Rail and three urban transportation projects shows how four different accounting framings bring wide variations in cost per metric tonne of GHG emissions reduced. In our analysis, life-cycle GHG emissions are joined with full cost accounting to better understand the benefits of cap-and-trade investments. Considering only public subsidy for capital, none of the projects appear to be a cost-effective means to reduce GHG emissions (i.e., relative to the current price of GHG emissions in California’s cap-and-trade program at $12.21 per tonne). However, after adjusting for the change in private costs users incur when switching from the counterfactual mode (automobile or aircraft) to the mode enabled by the project, all investments appear to reduce GHG emissions at a net savings to the public. Policy and decision-makers who consider only the capital cost of new transportation projects can be expected to incorrectly assess alternatives and indirect benefits (i.e., how travelers adapt to the new mass transit alternative) should be included in decision-making processes.  相似文献   

8.
ABSTRACT

The Belt and Road (B&R) initiative was introduced by the Chinese government to promote the worldwide economic development and multilateral cooperation between China and the associated countries. As a crucial part of global supply chains, transportation plays a key role to ensure the implementation of the B&R. Safety is one of the issues with great importance in transportation research. However, its foci have been expanded from traditional risk through security to resilience and sustainability. Resilience has attracted considerable interests from both researchers and practitioners across different research domains in recent years. Various studies have been conducted on transportation resilience from different perspectives. Consequently, different definitions have been developed to define and describe resilience. This paper presents a systematic review on transportation resilience with emphasis on its definitions, characteristics, and research methods applied in different transportation systems/contexts. It aims to figure out what transportation resilience is and what kind of essential characters it usually has. More importantly, research challenges are analysed and a future research agenda on the resilience of transportation systems is proposed. This paper will provide comprehensive insights into understanding the transportation resilience, as well as establish new horizons for relevant research topics within the context of the B&R.  相似文献   

9.
ABSTRACT

A transport initiative, like any kind of public action, has an impact on the monetary cost, time cost, efficiency and comfort of the transportation of goods and people, in particular transport infrastructure investments. All such initiatives are subject to cost benefit analyses at the national and EU level to know whether the present value of total net benefits including environmental impacts exceeds their cost. However, several important policy issues remain unresolved in standard evaluation procedures. One issue is whether the so-called direct measurement of user benefit, which consists of quantifying changes in surplus of the users of the transport system, captures all welfare generated in the economy. Another issue is how the gains (or possibly losses) of a transport initiative are distributed among regions. The aim of this article is to perform a systematic and quantitative analysis of the socio-economic and spatial impacts of alternative transport investments by carrying out scenario simulations in order to improve the understanding of the impact of transportation policies on the short- and long-term spatial development in Latvia. The general result from the scenario simulations is that rail projects seem to be more effective in terms of promoting regional economic activity than road projects.  相似文献   

10.
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.  相似文献   

11.
Having an effective public participation in transportation planning and project development processes has been a major concern for developed countries. In the United States, for instance, all state Departments of Transportation are subject to the Transportation Equity Act (TEA-21) that formally requires public involvement in transportation planning. Since transportation planning involves public resources and values, judgments by the public should play a key role in determining final decisions. Therefore, all these agencies are required not only to disseminate information to the public, but also to solicit and consider public opinion in forming transportation policy. This work presents a decision support model, with public involvement and public oversight, to help policy makers select appropriate transportation projects for implementation. Since focus groups will face multiple objectives and inexact information in the process, a hybrid model of fuzzy logic and analytical hierarchy process (AHP) is proposed. A set of ‘if–then’ rules based on Weber’s psycho-physical law of 1834 is presented to reason from fuzzy numbers to capture essential subjective preferences, pairwise, among the alternatives. The AHP is then incorporated to estimate preference allotments among alternatives. An example application of the suggested method is provided seeking public approval of an appropriate public bus transportation system choosing between one run by municipal authorities and one run by private agencies to show how this procedure works.
Turan ArslanEmail:
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12.
Recent developments in intelligent transportation systems pose new challenges and opportunities for urban transportation planning. To meet these challenges and to exploit these opportunities, a framework for a new transportation planning methodology has been developed. The methodology operates in a computer environment, called PLANiTS (Planning and Analysis Integration for Intelligent Transportation Systems), designed to facilitate the entire planning process form problem identification, through idea generation and analysis, on to prioritization and programming. To assist in problem identification, PLANiTS provides graphic representation of current conditions, including traffic, air pollution, accidents, and projections of future conditions. A computerized knowledge base, containing information about possible strategies and their effects, and a model base, containing transportation and other analysis models, are used to guide the user in identifying potentially effective strategies and performing the appropriate analysis. To facilitate the use of these tools, PLANiTS provides computer support of group processes such as brainstorming, deliberation, and consensus seeking. PLANiTS is designed for use in urban transportation planning at the local, regional, and state levels; it is intended to support a variety of participants in the planning process including transportation professionals, decision makers in transportation agencies (often local elected officials), citizens, and interest groups. Recognizing that transportation planning is essentially a deliberative, political process, PLANiTS is designed to inform and facilitate, but not replace, the political decision-making process.  相似文献   

13.
Abstract

This paper investigates a transportation scheduling problem in large-scale construction projects under a fuzzy random environment. The problem is formulated as a fuzzy, random multi-objective bilevel optimization model where the construction company decides the transportation quantities from every source to every destination according to the criterion of minimizing total transportation cost and transportation time on the upper level, while the transportation agencies choose their transportation routes such that the total travel cost is minimized on the lower level. Specifically, we model both travel time and travel cost as triangular fuzzy random variables. Then the multi-objective bilevel adaptive particle swarm optimization algorithm is proposed to solve the model. Finally, a case study of transportation scheduling for the Shuibuya Hydropower Project in China is used as a real world example to demonstrate the practicality and efficiency of the optimization model and algorithm.  相似文献   

14.
Recent efforts to emphasize social equity in transportation are emerging as local, regional and national governments have set initiatives to identify, existing and potential, disproportionate impacts to low-income and minority populations, also referred to as transportation justice (TJ). Currently, there are suggested methods for identifying transportation justice areas; however, there is no streamlined method instituted across transportation agencies. Each jurisdiction identifies transportation justice (or environmental justice) areas based on their own methodology, typically based on either average regional thresholds, graduated thresholds, or a more unique in-house index methodology. This research explores and evaluates existing methods and develops a rigorous and comprehensive method called the Transportation Justice Threshold Index Framework (TJTIF) using Geographic Information Systems (GIS), as well as factors based on demographics, socio-economics, and transportation/land use. The framework is applied to a case study region in Pennsylvania reflective of the Marcellus Shale impact area, highlighting Sullivan County, PA. The methodology and the case study application serve as an example for how transportation agencies throughout the country can promote social sustainability and enhance transportation equity.  相似文献   

15.
In recent years, increasing attention has been drawn to the development of various applications of intelligent transportation systems (ITS), which are credited with the amelioration of traffic conditions in urban and regional environments. Advanced traveler information systems (ATIS) constitute an important element of ITS by providing potential travelers with information on the network's current performance both en-route and pre-trip. In order to tackle the complexity of such systems, derived from the difficulty of providing real-time estimations of current as well as forecasts of future traffic conditions, a series of models and algorithms have been initiated. This paper proposes the development of an integrated framework for real-time ATIS and presents its application on a large-scale network, that of Thessaloniki, Greece, concluding with a discussion on development and implementation challenges as well as on the advantages and limitations of such an effort.  相似文献   

16.
Abstract

In comparison to personal travel, freight movements within large metropolitan areas are much less studied. Most conventional transportation models and planning analysis that disregarded freight flows have been criticized on the plausibility of their results and conclusions. To alleviate these problems, this study proposes a non-survey based approach to assemble and process freight data in a systematic way. A freight origin–destination (OD) matrix of freight flows can be developed using secondary data sources. The estimated freight flows can be loaded together with conventional passenger flows onto the regional highway network of a large metropolitan area. As a case study, this non-survey based approach was applied to build a freight OD and study the traffic flows in Los Angeles. It concluded that this approach can be used to analyze urban freight movement in a low-cost way in which planning agencies can overcome the common omission of freight flow information in their transportation plans.  相似文献   

17.
Reliability in cost estimates in publicly funded projects is more important today than ever with increased governmental funding to infrastructure projects and associated accountability requirements, but surface transportation projects, large and small, in the United States have a legacy of cost overruns. The problems with these overruns start with the cost estimation process before projects begin. Studies have shown that early cost estimations reflect best-case scenarios rather than realistic expectations, and have attributed technical, economic, psychological, and political reasons for underestimation. The primary objectives of this research were to determine how costs have been presented and updated in environmental impact statements, to identify endemic technical problems with cost estimation during the environmental review of surface transportation projects, and to develop recommendations for improving cost estimation and disclosure. Cost estimation methods were analyzed from the documents of 100 projects, including draft environmental impact statements, final environmental impact statements, and records of decision. The study concluded that the lack of guidance on how to include cost estimation in environmental review revealed itself in the level of detail and attention given to estimating costs. Agencies omitted or included various aspects of cost estimation randomly. Professional organizations should fill the gap of the need for specific guidance to cost estimation for environmental review so it can evolve as a state of the practice.  相似文献   

18.
This paper investigates the costs of controlling some of the environmental impacts of motor vehicle transportation on groundwater and on surface waters. We estimate that annualized costs of cleaning-up leaking underground storage tanks range from $0.8 billion to $2.1 billion per year over 10 years. Annualized costs of controlling highway runoff from principal arterials in the US are much larger: they range from $2.9 billion to $15.6 billion per year over 20 years (1.6–8.3% of annualized highway transportation expenditures). Some causes of non-point source pollution were unintentionally created by regulations or could be addressed by simple design changes of motor vehicles. A review of applicable measures suggests that effective policies should combine economic incentives, information campaigns, and enforcement, coupled with preventive environmental measures. In general, preventing water pollution from motor vehicles would be much cheaper than cleaning it up.  相似文献   

19.

Both the geographic information system (GIS) and transportation modeling environments have seen continually developing analytic concepts and techniques. However, these developments have seldom resulted in the integration of GISs and transportation models. This paper explores the potential inherent in merging of these environments through a systematic investigation of the fundamental basis of integration. To do this, the traditional four step transportation modeling process is extended to include input and output steps. We then define functional components for GIS data handling — data management, manipulation, and analysis. The steps of modeling are matched against the list of GIS data handling functions within a matrix‐based framework. GIS functions that enhance a land‐use based urban transportation modeling process are then categorized. Conclusions are drawn and directions for future developments are discussed.  相似文献   

20.
Understanding links from new highway construction or capacity expansion to regional growth patterns is crucial for transportation planners and policy makers. In this paper, we incorporate a lagged adjustment regional growth model into a quasi-experimental research design to examine the association between new highway investments and land use change in three California counties. Our study areas provide a mix of urban, small town, and exurban highway projects in order to explore the different effects across project types and geographic contexts. The central finding of this research is that while improvements in surface transportation infrastructure can have large impacts on growth patterns, the nature of the effect depends on the context of the highway investment.  相似文献   

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