As a typical car-dependent city,Los Angeles(LA) is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA’s geologic conditions and civil circumstances,we argued that the relationship between LA’s low-density pattern and car dependence is more involved than previously deemed simple causality. The low density should be primarily credited to the spacious requirement of the mining industry,frequent earthquakes and multiethnic population of the city. Oil reserves in LA fueled its economic boom and fast urbanization that coincided with the start of mass production of cheap cars,and cars became medium-priced consumables for average families. Politicians preference for short construction-period projects enabled fast establishment of LA’s highway infrastructure. The popularity of car use in return faciliatated further development of the low-density pattern of the city. The low-density urban form and car dependence created environmental and social problems for LA. Looking at P. R. China’s motorization and urban development,we found that the trajectory of Beijing’s motorization between 1978 and 2003 coincides with that of the U.S. in the 1910s and 1920s. Lessons from LA’s urban and transportation development should be suggestive to China’s urban and transportation planning. As a typical car-dependent city, Los Angeles (LA) is extensively used as an example in research to illustrate car influences on city form. Focusing on the features of LA’s geologic conditions and civil circumstances, we argued that the relationship between LA’s low- density pattern and car dependence is more involved than previously deemed simple causality. The low density should be credited to the spacious requirement of the mining industry, frequent earthquakes and multiethnic population of the city. Oil reserves in LA fueled its economic boom and fast urbanization that coincided with the start of mass production of cheap cars, and cars became medium-priced consumables for average families. Politicians preference for short construction-period projects enabled fast establishment of LA’s highway infrastructure. The popularity of car use in return faciliatated further development of the low-density pattern of the city. The low-density urban form and car dependent created environmen tal and social problems for LA. Looking at PR China’s motorization and urban development, we found that the trajectory of Beijing’s motorization between 1978 and 2003 coincides with that of the US in the 1910s and 1920s. Lessons from LA’s urban and transportation development should be suggestive to China’s urban and transportation planning.