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Abstract: The persistent infrastructure underinvestment coupled with a significant growth in commercial and non-commercial transportation demand has rendered the US transportation infrastructure unprepared for current and future demands. A significant improvement in the condition of the US transportation infrastructure must be grounded on a more sustainable and proactive approach to address the existing gap between short-term commitments and long-term needs. This paper demonstrates in quantitative terms the value of long-term investments to overcome the historical impediments to infrastructure rehabilitation, including the need for a proactive political structure that compensates for the apparent lack of public accountability, and for the poor understanding of the socio-economic effects caused by transportation infrastructure failures. Such a process could avoid impending catastrophes. This paper presents a modeling paradigm that accounts for multiple stakeholder perspectives and relates the formulation of public policy to a long-term horizon through the modeling of the transportation infrastructure as a system of systems. The methodology enables involved stakeholders and decision makers to visualize their shared interests and to promote coordinated individual decisions in order to achieve a more acceptable level of the overall system of systems objectives. To illustrate the relevance of the proposed modeling approach, we apply it to a bridge maintenance problem and we discuss the synthesis of existing engineering practice with socio-economic factors that aids in streamlining long-term infrastructure goals with immediate short-term needs. The insights obtained from the proposed system of systems methodological approach point to the need to adopt a more forward-looking and collaborative public policy for infrastructure maintenance. [Copyright &y& Elsevier]

Abstract: Understanding the contextual factors associated with why adults walk is important for those interested in increasing walking as a mode of transportation and leisure. This paper investigates the relationships between neighborhood-level sociodemographic context, individual level sociodemographic characteristics and walking for leisure and transport. Data from two community-based studies of adults (n =550) were used to determine the association between the Area Sociodemographic Environment (ASDE), calculated from U.S. Census variables, and individual-level SES as potential correlates of walking behavior. Descriptive statistics, mean comparisons and Pearson’s correlations coefficients were used to assess bivariate relationships. Generalized estimating equations were used to model the relationship between ASDE, as quartiles, and walking behavior. Adjusted models suggest adults engage in more minutes of walking for transportation and less walking for leisure in the most disadvantaged compared to the least disadvantaged neighborhoods but adding individual level demographics and SES eliminated the significant results. However, when models were stratified for free or reduced cost lunch, of those with children who qualified for free or reduced lunch, those who lived in the wealthiest neighborhoods engaged in 10.7min less of total walking per day compared to those living in the most challenged neighborhoods (p <0.001). Strategies to increase walking for transportation or leisure need to take account of individual level socioeconomic factors in addition to area-level measures. [Copyright &y& Elsevier]

Abstract: This paper applies the -convex model in order to investigate the technical efficiency of a representative sample of US airlines over the period 1998–2010. The results are mixed and reveal that US airlines’ efficiency can be influenced by the size of the airline, mergers and acquisitions, and by time. Policy implications are derived. [Copyright &y& Elsevier]

Abstract: This paper and the proposed formulation contribute to an apparent gap in transit research design by integrating equity considerations into the transit frequency-setting problem. The proposed approach provides a means to design transit service such that equitable access to basic amenities (e.g., employment, supermarkets, medical services) is provided for low-income populations or disadvantaged populations. The overarching purpose is to improve access via transit to basic amenities to: (1) reduce the disproportionate burden faced by transit dependent populations; and (2) create a more feasible transportation option for low-income households as an opportunity to increase financial security by reducing dependence on personal autos. The formulation is applied to data from a mid-sized US metropolitan area. The example application illustrates the formulation successfully increases access to employment opportunities for residents in areas with high percentages of low-income persons, as well as demonstrates the importance of considering uncertainty in the locations of populations and employment. [Copyright &y& Elsevier]

Abstract: In this paper, an analytical framework integrating delay, fare, and complaints with passenger air travel has been laid out. Examining aggregate monthly data for US domestic air travel, we have identified causal relationships among fare, complaints, and levels of delay. An analytical framework is proposed that formalizes these relationships in an integrated manner. This integrated framework is then estimated in a set of simultaneous equations by using 118months of data from January 1997 to October 2006. Results show that complaints are influenced by levels of delays. However, complaints are positively influenced by average yield. These findings lead us to support the central hypothesis that complaints are responsive to levels of delays, but they tend to vary according to fare. That is, air travelers are less likely to complain in return for lower fares, even when faced with the same or even higher levels of delays. These findings have important policy implications, including the passengers’ bill of rights and regulator’s choice between market and operational performances. [Copyright &y& Elsevier]

Abstract: Past studies of economies of scale in transit have tended to treat the transit industry as a set of similar agencies that have the same cost structure, and have conducted an analysis for the entire range of agency size using a single regression function. This may have caused problems in the interpretation of analysis results because agencies of different sizes that may have different cost structures are treated as a homogeneous data set. In this paper, I examine the issues of economies of scale in the provision of fixed-route bus transit service in the USA, using level of contracting as a variable to classify agencies into three different size groups. In this analysis, using a significantly larger pooled data set (compared to previous studies) constructed from the National Transit Database of the US Federal Transit Administration from 1992 to 2000, I found that agencies with different levels of contracting exhibit very different relationships between cost per vehicle hour and agency size. Applying the observed range of agency size, I also found diseconomies of scale for all agency sizes with all levels of contracting, even when I utilized a quadratic function for the regression equation. While the analysis is limited since the model did not control for many other explanatory variables, the findings suggest that the level of contracting is possibly an important variable, among many attributes of transit systems, with which to classify agencies into different size groups, each of which has a different transit cost structure. [Copyright &y& Elsevier]

Abstract: US Department of Transportation research funds historically have been awarded on the basis of competition and merit review. Over the last 15 years, however, transportation research programs have seen dramatic growth in earmarking, a practice in which Congress designates research funds for specific institutions named in legislation. This paper discusses driving forces for and potential risks associated with this practice and presents data on earmarking trends from five USDOT agencies. [Copyright &y& Elsevier]