Determinants of Automobile Use: A Comparison of Germany and the U.S

Germany and the U.S. have among the highest motorization rates in the world. Yet Americans make a 40% higher share of their trips by car and annually drive twice as many kilometers per capita as Germans. Automobile use is linked to unsustainable trends such as climate change, oil dependence, traffic fatalities, congestion, and obesity. International differences in car use can be attributed to socioeconomic and demographic factors, spatial development patterns, transport policies and culture. Arguably, differences in socio-economic and demographic factors together with denser, more compact spatial development patterns, and more automobile restrictive transport policies in Germany can help explain less car use there. Using two comparable individual level national travel surveys this paper empirically investigates the role of socio-economic and demographic factors, spatial development patterns and transport policies in explaining differences in automobile use in Germany and the U.S. In both countries higher population density, a greater mix of land uses, household proximity to a transit stop, fewer cars per household, and higher car operating costs are associated with shorter daily automobile travel distances. However, considerable differences remain: for example Americans in settlements of more than 5,000 people per square kilometer drive as many kilometers as Germans in settlements with five times lower density. A multivariate analysis shows that—controlling for socioeconomic factors—population density and automobile operating costs play a role in explaining differences in travel. This is good news for the U.S., since denser more mixed-use developments and more automobile restrictive policies can help increase the sustainability of the transport system. In Germany, travel behavior is more homogeneous across all groups of society and in all spatial settlement patterns than in the U.S. This is potentially related to historically higher gasoline prices and greater availability of alternative means of transport, which provide incentives for walking, cycling, and transit use.