This paper examines how demographic changes can help explain changes/differences in personal transport using both International Energy Agency country panel
regressions and decompositions of U.S. household data. An environmental Kuznets curve for per capita road energy use was rejected; instead, the relationship between
income and road energy was found to be monotonic. The ideas that more densely populated countries have less personal transport demands, the young drive more, and smaller households mean higher per capita driving were confirmed. The household decompositions indicated that changes in demand were more important than compositional changes; yet, during some periods the compositional change component was considerable.