Introduction and Overview

Federal, state, and local governments in the United States and Germany aim to reduce petroleum use and associated greenhouse gas (GHG) emissions from transport. In 2010, the transport sector was responsible for 20 percent of GHG emissions in Germany compared to 31 percent in the U.S.[1]  In both countries the vast majority (~95 percent) of energy for transport came from petroleum and carbon dioxide (CO₂) accounted for about 95 percent of GHG emissions from transport.[2]

Automobiles, light trucks, and public transport were responsible for roughly two-thirds of transport GHG emissions in each country—accounting for 13.5 percent of total CO₂ emissions in Germany and 22.7 percent in the U.S.[3]  Annual per-capita CO₂ emissions from ground passenger transport in the U.S. were three times greater than in Germany: 3,800 vs.1,200kg.[4] Even adjusting for economic activity, CO₂ emissions from passenger transport per unit of gross domestic product (GDP) were 2.4 times greater in the U.S. than in Germany.

Tackling emissions from ground passenger transport has proven difficult, because improvements in technological efficiency of cars and fuels can be off-set by heavier vehicles, more powerful engines, and longer travel distances (the so-called “rebound effect”).[5] Compared to the energy and industry sectors, passenger transport emissions are more difficult to regulate, because travel behavior depends on individual decisions about residential location, vehicle ownership, transport mode choice, number of trips, and travel distance.[6]

This article first compares trends of CO₂ emissions[7] from passenger transport in Germany and the U.S. since 1990. Next it discusses policies that can help decrease CO₂ emissions from passenger transport through technology and changes in travel demand. The analysis concludes with policy lessons for both countries.

Many Similarities between Germany and the U.S.

Germany and the U.S. present many similarities that make a comparison of CO₂ emissions from transport and related policies meaningful. Both are western democracies with market economies, a high standard of living, and federal systems of government in which the interaction between federal, state, and local governments shapes transport policies.[8] Both countries have large networks of limited access highways, a similar share of licensed drivers (70 percent) in the population, and an important automobile industry.[9] In both countries most suburban development occurred after World War II during periods of rapid motorization.  In Germany and the U.S. the automobile is an important status symbol. Both countries have among the highest motorization rates in the world. However, compared to Germans, Americans own 30 percent more vehicles: 766 versus 585 cars and light trucks per 1,000 population.[10]