The effects of the past quarter century of deregulation on the transportation industry in the United States are many and varied. Impacts have been felt at the level of the industry as a whole, at the level of mode-based industry sub-groups, and at the level of individual firms. Analyses and depictions of these impacts have appeared in numerous books and journal articles. In this paper a new, empirically based, methodological approach to industry analysis will be employed to evaluate and illustrate the impacts of deregulation on the relevant levels of this industry in terms of its largest firms. The results of this analysis will be seen to be largely complementary to previous analyses, but will go beyond them in being able to identify in quantitative terms differential impacts of regulatory and other events on individual firms, groups of firms, and the industry from a unified methodological point of view. A later version of this paper appeared in Technovation, volume 5, issues 1–3, October 1986, Pages 35-60, doi 10.1016/0166-4972(86)90043-X.