Journal of Infrastructure Systems

Urban dispersion processes in metropolitan areas have led to patterns of suburbanization and urban sprawl. These processes are inseparably connected with the shift of private mobility from green transport modes to cars. Urbanization is always accompanied by the development of physical infrastructure, which requires huge investments and determines the structure of a city over long periods of time. Moreover, it cannot be readily adjusted to changing patterns of the demanded services, e.g., triggered by population shrinking. Thus, the impacts of urban sprawl on the local urban infrastructure asset represent complex and important issues to be considered in this context. This comparative study, conducted for the metropolitan regions of Nagoya in Japan and Munich in Germany, correlated six land-use patterns and two mobility parameters with the complexity of urban infrastructure by multiple regression modeling. The result confirms the impact of density on public infrastructure stock and additionally shows that there are other relevant parameters of urban sprawl beyond density, such as the concentration of urban development. The saving potential, which was calculated as the monetary cost difference between the most infrastructure-efficient and most inefficient municipalities, is 85% on average for Munich and 57% for the Nagoya region for sewage, primary schools, and local roads.

The financial crisis has substantially aggravated shortages of public funds all over the world, particularly in many developed countries. After the expiration of investments made within the framework of public economic recovery plans, the availability of public funds for infrastructure investments will be subject to severe constraints. These conditions require that scarce available funds be spent in an efficient and effective manner. Evaluation methods to select and prioritize infrastructure projects of an investment package often presuppose that infrastructure projects are independent of one another. However, it is inherent in the nature of transport networks that links are interdependent and that changes in one link will affect other parts of the network. Some infrastructure projects might be characterized by substitutive interdependence, while others might interact in a synergistic context. Thus, the cost and benefits of a project are strongly dependent on the realization of other projects. This paper confronts this issue by comprehensively addressing the nature of the problem to derive an optimal set of investment projects. The approach utilizes a dynamic mixed integer algorithm, and the complexity of the combinatorial problem is reduced by elaborating on a heuristic method. Under application of these requisites, this paper develops a framework for integrating the interdependence between infrastructure projects in cost-benefit analysis. Results obtained from an example application related to investments made in the Trans-European Network (TEN-T) emphasize the importance and relevance of considering interdependence for evaluating the investment potential of infrastructure projects.

Road networks can be considered local public goods. Hence, if they are to be efficient social choices from an economic perspective, their spatial benefit incidence should be equal to their cost burden in each region. An analysis of benefit incidence should consider not only a usual scenario but also a disaster scenario because the redundancy effect is expected to reduce the amount of economic damage incurred during a disaster. The authors’ research group has developed a spatial computable general equilibrium model (RAEM-Light) that can be applied to small spatial regions. The RAEM-Light model was used to analyze the benefit incidence in the development and maintenance stages of proposed road networks under a usual and a disaster scenario. The spatial incidence of the economic effect of road investment differs between the usual and the disaster scenarios for both the development and maintenance stages. As Japan becomes more decentralized, it will become more important to determine the optimum allocation of the road-network cost burden among local governments, taking into account differences in the spatial benefit incidence at each stage and in each scenario. However, to minimize the economic losses incurred by a disaster such as the Tohoku earthquake (March 11, 2011), more centralized decision making may be necessary, although this is not efficient social choice from an economic perspective.

Standard cost-benefit analysis is based on a static setting, allowing the decision to be made of whether or not a new infrastructure should be built, but not allowing the conclusion to be made of if it would be preferable to build it right now or in the future. In this paper, the optimal timing for building a road within a cost-benefit framework is addressed. A general approach for choosing the optimal timing, taking into account the characteristics of a road infrastructure, is proposed. A model of the expected net present value with two sources of uncertainty (gross domestic product growth and fuel prices) is proposed. Both these variables are assumed to be stochastic, so Monte Carlo simulation is used for the implementation of the model. A methodology is also proposed to estimate the thresholds that define the optimal starting time for the infrastructure. The model is applied to a real infrastructure currently under development and the rules that define the optimal timing for starting its construction are analyzed.

Pavement management systems inventory historical and current conditions of roadway networks, predict the future conditions of such networks, and suggest schedules for maintenance, repair, and rehabilitation activities. Such systems typically rely on a composite condition index, a one-dimensional and often discrete measure of the overall structural health and/or serviceability of pavement. The index is used during deterioration modeling, user and agency cost estimation, and selection and scheduling of maintenance activities. Pavement can suffer from a large number of related but distinct distresses. Difficulties associated with unobserved heterogeneity have hampered efforts to accurately model deterioration through composite condition indexes. At the same time, optimization techniques used to generate recommended maintenance plans have been shown both to be sensitive to deterioration model specification and to become computationally intractable as condition data increase. This research describes how a large network of related sections of pavement, each one of which may be plagued by a number of different distresses, can be managed without reducing condition data to a composite index. The use of approximate dynamic programming mitigates the curse of dimensionality that has haunted distinct Markov decision problem formulations of the maintenance optimization problem and limited their complexity. A computational study illustrates how the proposed approach leads to more sophisticated maintenance decision rules, which can be used to ensure the suggestions of pavement management systems more closely match engineering best practices. The use of multidimensional condition data can also yield more accurate deterioration models and cost estimates. The techniques introduced in this paper in the context of pavement management could easily be applied within any infrastructure management system.

This article outlines issues to be tackled when considering increases in biofuel usage in the European Union (EU) and examines a potential scheme to increase the use of biofuels in the road transport sector; the development of biofuels corridors. An EU biofuels corridor is defined as a long-distance and cross-border route on the Trans-European Transport (TEN-T) Network roads on which blends with a high biofuel content (referred to as high blends) are offered at regular intervals along the entire route. The article first defines the current framework of EU biofuels development. A case study on the feasibility of one possible EU biofuels corridor, from Rotterdam, Netherlands, to Constanta, Romania, is analyzed along four potential biofuels corridor designs (under different future scenarios). The case study includes interviews with key stakeholders, transport flows analysis, refueling infrastructure, and biofuels policy in the relevant member states. The results are extrapolated to the complete EU level in order to assess the potential effect of the biofuels corridor approach as a measure of stimulating the use of biofuels. It is concluded that EU biofuels corridors can increase the use of biofuels. However, if applied as a stand-alone measure a maximum contribution is limited. The effectiveness of biofuels corridors is not larger mainly due to the fact that the transport flows on the TEN-T Network roads are not representative of actual fuel sales at stations on this network (i.e., motorway stations). In addition, various recommendations are made for further research.

The planning for pedestrian evacuation in large public-gathering buildings is important because pedestrians are vulnerable to various types of emergency events. One of the most critical measures of the preparedness of a building during these events is its evacuation guidance. This paper proposes a method for designing evacuation guidance systems in complex building spaces by solving a maximum-coverage problem with side constraints of number of signs and evacuation routes. The solution of the problem is difficult to find in general, so the problem is solved in two steps. The first step generates an ideal evacuation guidance system with an unlimited number of signs. In the second step, the ideal system is reduced to the actual guidance system with a reasonable number of signs by constraining the number of signs and maximizing the sign coverage. There are two reasons for using the ideal system as a basis for generating the actual guidance system. First, the solution space of the maximum-coverage problem is greatly restricted by limiting the sign installation choices to the candidate locations found in the ideal system. Second, calculating evacuation routes for the actual system is not necessary because the routes are readily available from the ideal guidance system. Finally, an example based on a transportation terminal is presented to validate the methodology. The results show that the proposed methodology is effective and can be used for supporting emergency evacuation planning for buildings.

Cost overruns occur in the majority of transport infrastructure projects in the European Union. An average project is 15–20% over budget, and one in four is above that. Deviations in cost, duration, and environmental impact are especially problematic because such investments add up to billions of Euros and have significant impacts. Based on a recent evaluation of investment for transport and energy networks project in Europe (EVA-TREN) and critical review of the state of the art, this contribution investigates the causes of deviation between project appraisals and real outcomes. Projects with partial or narrow-framed assessments are found to be more likely to face changes in design and technical and/or in environmental specifications and, therefore, delays in implementation. This, in turn, leads to significant cost overruns. The analysis indicates that effective and efficient implementation requires a level of project maturity that essentially hinges on the robustness of the scientific expertise that underlies project appraisal and on the thoroughness of stakeholders’ involvement in the decision process. On this basis, the paper proposes a new framework for organizing transport infrastructure assessments and for monitoring the implementation process.

The original main aim of high-speed rail (HSR) was to link big metropolitan areas 400–600 km apart. Recently, intermediate HSR stations have also been created in suburban areas or small cities within the limits of metropolitan areas (up to 100 km), opening up new metropolitan transportation opportunities, notably the strengthening of inward and outward commuting and through traffic across the metropolis. The argument advanced in this paper is under what conditions HSR could facilitate the development of small HSR suburban cities as special subcenters of the metropolitan area with particularly good connections to the metropolitan center and to other distant metropolises. The paper focuses on a comparative study of this new type of metropolitan HSR by analyzing the Madrid (Toledo, Segovia, and Guadalajara stations), Spain, and the London (Ashford, Ebbsfleet, and Stratford stations) cases. Infrastructure layout, station typologies, and rail services are compared together with each city’s territorial contexts, activities, and connections with other transport modes. This case-study approach, taking account of specific circumstances and contexts, facilitates the understanding of the HSR impact on metropolitan development, offering new transport alternatives.

This paper develops a methodology to define the optimum length of railway track that would undergo maintenance work by one tamping machine. The acquisition and logistic costs associated with the use of this type of machine are very relevant in the context of track maintenance. However, no systematic approach was found in the literature that could help managers recognize the machines’ real capacity, which seems to be more conditioned by the track’s availability for maintenance than by the machine’s performance. The methodology presented in this paper takes into account the execution capacity of the machine in a scenario in which the intervention schedule is optimized from a long-term perspective. It employs a metaheuristic process (simulated annealing) to deliver an optimized intervention schedule and the model is applied to several track length configurations. A trade-off approach is therefore adopted, confronting the minimum logistic costs with the fixed costs of the machine. The implementation of the algorithm showed significant cost reduction. However, the results of the model showed a deviation of the minimum cost solution from the quality standards. Further research could provide more insight into quality standards through its integration into a multiobjective analysis.