摘要: |
Recent trends show that sport utility vehicles, mini-vans, and light-duty trucks (SUV-VTs) are progressively replacing passenger vehicles in the U.S. fleet. The change in vehicle fleet composition raises several interesting questions. For instance, who are the primary drivers of these vehicles and for what types of trips are they being used? Anecdotal evidence suggests that SUV-VTs are used primarily for suburban driving, by parents taking children to an assortment of recreation activities. There are questions of equity associated with use of SUV-VTs. These revolve around such issues as assigning vehicle emissions to those producing the emissions, increased energy consumption, and appropriateness of the Corporate Average Fuel Economy (CAFE) standards. In this paper the authors use data from the 1995 Nationwide Personal Transportation Survey (NPTS) database to analyze the current fleet with respect to who are driving the vehicles, what types of trips are the vehicles being used for, and where the primary accumulation of vehicle miles of travel (VMT) is occurring. Specifically, they explore three hypotheses. In the first, they hypothesize that relatively wealthy Americans are potentially responsible for a greater share of mobile source emissions and that certain proportions of VMT accumulation are related to gender differences. This implies that they expect to find households with higher incomes owning a disproportionate share of vehicles with low fuel efficiencies and/or higher emissions. In their second hypothesis, they propose that a disproportionate share of SUV-VT travel is occurring in the suburbs and 2nd cities as opposed to the urban areas. As part of this examination, they explore how trip-making activities vary between the suburbs/2nd cities and urban areas, controlling for vehicle type and a variety of other factors, such as gender. Finally, for the third hypothesis the authors expect to find that SUV-VTs are used very similarly to passenger vehicles. For over 20 years, SUV-VTs have enjoyed exemption from the CAFE standards. Clean air regulations have continuously allowed SUV-VT tailpipe emissions to be much higher on a per mile basis than those from passenger cars. The paper is organized around these three central hypotheses, exploring each in turn. At the conclusion of the paper, the authors offer a summary of their major findings as well as a brief commentary on the major policy issues. |