Who are the drivers of peak car use?

This study investigates the contribution of the aging of the population and changes in travel behavior by age group to peak car use in France, Germany, Great Britain, Japan, Norway, and the United States. The terms peak car use, peak car travel, and peak car hypothesis have been coined for the recent trend reversal in car travel development observed in some industrialized countries. In the study countries, car travel was characterized by growth for a long time but started to show signs of stagnation or even decrease in the past decade. The authors analyze underlying travel trends since the mid-1990s and use a trend decomposition based on descriptive statistics from national travel surveys and Laspeyres indices. The results indicate that relevant developments have different weight in shaping peak car use in the study countries. In many places, the aging of the population has been an important contributor to peak car use. In Japan, aging was the most important factor limiting growth of car travel. In all study countries except the United States, where car ownership by seniors has not grown, increasing car ownership and car use by seniors have contributed to increasing car travel and thus have exerted a damping influence on peak car use. Another important development was new travel trends of young adults. In three countries, the contribution of young adults to peak car use is crucial: if young adults' car ownership and car mode share had not decreased, results would not have shown declining total car kilometers per capita in Germany and would have shown much stronger increases in Great Britain and Norway.