78 research outputs found

    The Effects of the Emission Cost on Route Choices of International Container Ships

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    Maritime freight shipping has increased significantly and air pollution from international ships has grown accordingly, having serious environmental effects all over the world. This paper analyzes the effects of the emission cost on ocean route choices, focusing on international container ships. First, the paper formulates a freight network model that captures decisions and interactions of ocean carriers and port terminal operators in the maritime freight transport system. Then, the emission cost is calculated based on an activity-based approach as a component of the ocean transportation cost function. A case study is examined to find if the emission cost affects ocean route choices. The results indicate that the optimal ocean route and transportation cost are changed distinctively due to the emission cost. The research discusses how the emission cost plays a role in route changes and why ocean carriers have to consider these costs in their routing decisions

    Aggregate Relationships between Telecommunications and Travel: Structural Equation Modeling of Time Series Data

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    The purpose of this study is to explore the aggregate relationships (substitution, complementarity, or neutrality) between telecommunications and travel and to compare such relationships across transportation modes. This study first presents a conceptual model, considering causal relationships among travel, telecommunications, land use, economic activity, and socio-demographics. Then, based on the conceptual model, the aggregate relationships between telecommunications (local telephone calls, toll calls, and mobile phone subscribers) and travel (VMT, transit passengers, and airline PMT) are explored in a comprehensive framework, using structural equation modeling of national time series data spanning 1950-2000 in the U.S. At the most detailed level, individual and joint structural equation models for telecommunications and ground travel or airline travel were developed, using selected subsets of the endogenous variables, and then the causal relationships between the two were compared by mode. The model results suggest that most significant causal relationships between telecommunications and travel are complementary. That is, as telecommunications demand increases, travel demand increases, and vice versa. The only exceptions are the two causal relationships between transit passengers and mobile phone subscribers, which are substitutive. Furthermore, there are a number of neutral (zero net) effects of telecommunications on travel or vice versa. Overall, causal effects between telecommunications and travel are different among their modes. However, most of them are complementary regardless of the causal direction. At a less detailed level, composite indices for eight endogenous variable categories were constructed by combining the variables of a given category into a single composite indicator for that category through confirmatory factor analysis. Then, structural equation models for travel and wired (telephone calls) or mobile (mobile phone subscribers) telecommunications were estimated, using the composite indices and sociodemographic variables. The estimated models also support that the aggregate relationship between actual amounts of telecommunications and travel is complementarity, albeit asymmetric in directional weight. That is, as travel demand increases, telecommunications demand increases, and (to a lesser extent) vice versa. Consequently, the empirical results from both levels of structural equation modeling strongly suggest that the aggregate relationship (or system-wide net effect) between actual amounts of travel and telecommunications is complementarity, not substitution

    Identification of Causal Relationship between Attitudinal Factors and Intention to Use Transportation Mode

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    Based on the theory of planned behavior, this study identifies the causal relationship between attitudinal factors and intention to use transportation mode. A structural equation model was developed based on twelve hypotheses. The main findings and implications of this study are as follows. First, people who want to express themselves through cars have a high intention to use personal vehicles, and they purchase cars for this purpose. If the shared vehicle service provides a vehicle rental that reflects individual tastes, those who want to own the vehicle will use the shared vehicle. This could be a solution to the parking problem. Second, those who perceive travel as a disutility have a low intention to use public transportation. If fare discounts are applied when transferring public transportation and micro-mobility, it is expected that the use of public transportation will increase due to reduction of access time for public transportation. Third, people who like to drive have a high intention to use personal vehicles and micro-mobility. Providing space for driving cars as a leisure activity may be one of the ways to prevent traffic accidents that may occur in the future due to a mixed flow of autonomous vehicles and conventional vehicles

    Identification of Causal Relationship between Attitudinal Factors and Intention to Use Transportation Mode

    No full text
    Based on the theory of planned behavior, this study identifies the causal relationship between attitudinal factors and intention to use transportation mode. A structural equation model was developed based on twelve hypotheses. The main findings and implications of this study are as follows. First, people who want to express themselves through cars have a high intention to use personal vehicles, and they purchase cars for this purpose. If the shared vehicle service provides a vehicle rental that reflects individual tastes, those who want to own the vehicle will use the shared vehicle. This could be a solution to the parking problem. Second, those who perceive travel as a disutility have a low intention to use public transportation. If fare discounts are applied when transferring public transportation and micro-mobility, it is expected that the use of public transportation will increase due to reduction of access time for public transportation. Third, people who like to drive have a high intention to use personal vehicles and micro-mobility. Providing space for driving cars as a leisure activity may be one of the ways to prevent traffic accidents that may occur in the future due to a mixed flow of autonomous vehicles and conventional vehicles
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