ATTRIBUTE IMPORTANCE IN MULTIATTRIBUTE TRANSPORTATION DECISIONS

This report describes a study of the relative importance of various travel attributes as influences on commuters' choices among car, bus, and Bay Area Rapid Transit (BART) for traveling to work in the San Francisco Bay area. A sample of commuters were interviewed, and each was asked to rate his or her satisfaction with car, bus, and BART on each of the attributes studied. The relative importance of the attributes was inferred by examining these ratings and the relationships between the ratings and the usual choice of travel mode. The study differed from previous similar research in that attribute importance was measured with a statistic that estimated how much each attribute contributed to differences in utility among the choice alternatives. Most previous research failed to consider an essential component of the quantity measured by this statistic, namely, average differences in utility among alternatives caused by average differences among alternatives in the levels of each attribute. Among the attributes judged to be most important were safety from crime, seat availability, and dependable arrival, which are ordinarily not included in quantitative planning procedures such as travel demand forecasting and cost-benefit analysis. /Author/