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 circumstance...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. Off 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 constrnction-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 197g 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.展开更多
Urban eco-environmental degradation is becoming inevitable due to the extensive urbanization, popula- tion growth, and socioeconomic development in China. One of the traffic arteries in Shenzhen is an urban expressway...Urban eco-environmental degradation is becoming inevitable due to the extensive urbanization, popula- tion growth, and socioeconomic development in China. One of the traffic arteries in Shenzhen is an urban expressway that is under construction and that runs across environmentally sensitive areas （ESAs）. The environmental pollution from urban expressways is critical, due to the characteristics of expressways such as high runoff coefficients, considerable contaminant accumulation, and complex pollutant ingredi- ents. ESAs are vulnerable to anthropogenic disturbances and hence should be given special attention. In order to evaluate the environmental sensitivity along this urban expressway and minimize the influences of the ongoing road construction and future operation on the surrounding ecosystem, the environmental sensitivity of the relevant area was evaluated based on the application of a geographic information sys- tem （GIS）. A final ESA map was classified into four environmental sensitivity levels; this classification indicates that a large proportion of the expressway passes through areas of high sensitivity, representing 11.93 km or 52.3% of the total expressway, and more than 90% of the total expressway passes through ESAs. This study provides beneficial information for optimal layout schemes of initial rainfall runofftreatment facilities developed from low-impact development （LID） techniques in order to minimize the impact of polluted road runoff on the surrounding ecological environment.展开更多
基金Funded by Key Project of the Natural Science Foundation of China under the grant No. 40635026.
文摘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. Off 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 constrnction-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 197g 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.
文摘Urban eco-environmental degradation is becoming inevitable due to the extensive urbanization, popula- tion growth, and socioeconomic development in China. One of the traffic arteries in Shenzhen is an urban expressway that is under construction and that runs across environmentally sensitive areas （ESAs）. The environmental pollution from urban expressways is critical, due to the characteristics of expressways such as high runoff coefficients, considerable contaminant accumulation, and complex pollutant ingredi- ents. ESAs are vulnerable to anthropogenic disturbances and hence should be given special attention. In order to evaluate the environmental sensitivity along this urban expressway and minimize the influences of the ongoing road construction and future operation on the surrounding ecosystem, the environmental sensitivity of the relevant area was evaluated based on the application of a geographic information sys- tem （GIS）. A final ESA map was classified into four environmental sensitivity levels; this classification indicates that a large proportion of the expressway passes through areas of high sensitivity, representing 11.93 km or 52.3% of the total expressway, and more than 90% of the total expressway passes through ESAs. This study provides beneficial information for optimal layout schemes of initial rainfall runofftreatment facilities developed from low-impact development （LID） techniques in order to minimize the impact of polluted road runoff on the surrounding ecological environment.
