Comparative Study On The Urban Commuting CO₂ Emissions

Low carbon emission transportation development has become one of the priority strategies for coping with the global climate changes and realizing the sustainable development.We need to seek effective measures to solve the problems of environment pollution,energy and resource shortages,and also,we need to explore the scientific path for the low carbon emission transportation development to cope with the challenges of the continuous urban sprawl,population increase,and economic growths.This thesis used the following four projects' data to make the comparative study on the urban forms,commuting patterns,commuting CO₂ emissions and their sensitivity,and spatial distribution charaters of the commuting CO₂ emissions in the typical four rapidly developing cities of China and India?Beijing of China,Xi'an of China,Wuhan of China,and Bangalore of India?: National Natural Science Foundation of China?51178055-E0807?,Asia Pacific Network for Global Change Research?ARCP2011-07CMY-Han?,Australian Research Council Project?ARCDP1094801?,and National Natural Science Foundation of China?41371007?.Also,this thesis established the commuting CO₂ emission models,revealed the impact factors of the commuting CO₂ emissions and their spatial distributions,and also revealed the regulars and changing tendencies of the relationships among urban spatial parameters,transportation developments,commuting patterns and commuting CO₂ emissions.This thesis can provide the reference values for the policymakings of reducing the transport CO₂ emissions,and the development plans of low carbon and sustainable transport and urban development.This thesis has the following innovations:???This thesis proposed the method for calculating the household/individual commuting CO₂ emissions by zone in the entire urban areas.This method can avoid the uncontinuity of the spatial distribution statistics of the household/individual commuting CO₂ emissions in the urban areas.This method can aggregate and make descriptive statistics of the characters of the spatial distributions of the household/individual commuting CO₂ emissions by zones.Based on this method,this thesis found that the commuting CO₂ emissions in the areas along the ring roads and radial roads,and in the outer areas are larger than those in the inner cities,and the spatial distribution characters of the commuting CO₂ emssions are consistent with the spatial distribution characters of the household car availability.???Based on the characters of the non-normal distributions of the household/individual commuting CO₂ emissions,this thesis proposed to use the Tobit modeling method to fit the household/individual commuting CO₂ emissions and find the significant explanatory factors.This thesis found that: household separated by the ring roads and work unit types are significant factors of the commuting CO₂ emissions;compared with the existing studies,car availability has the largest impact on the commuting CO₂ emissions in Chinese and Indian cities,which is the most important factor for the increasing of the commuting CO₂ emissions in China and India,while in the developed cities in the Seoul metropolitan area of Korea,Oxfordshire,Cardiff,Kenilworth,and Southampton of UK,income has the largest impact on the commuting CO₂ emissions;polycentric urban form has significant effect in reducing the commuting CO₂ emissions.???This thesis proposed the calculation methods of the sensitivity analysis for the commuting CO₂ emission factors and commuting CO₂ emisisons.Based on the methods,this thesis found that: the vehicle occupancy's changes have larger impact on the CO₂ emission factor's changes than the fuel consumption's effect;commuting distance's changes have larger impact on the commuting CO₂ emission's changes than the CO₂ emission factor's effect,which manifest that commuting distance is the most sensitive factor of the commuting CO₂ emission,and the next is the vehicle occupancy.???Through the comparative study of the four case cities,this thesis found that: the increases in the commuting CO₂ emissions are several times larger than the increases in urban size,population,and economic developments in the monocentric sprawling cities;in the polycentric city,there exist large percentage of short distance trips and non-motorized traffic shares and small percentage of the car shares;as the distance from the city center increase,there exist not much increase of the commuting distance and CO₂ emissions and decreased car distance,which manifest that polycentric cities have the tendency of more sustainable transport development in the process of the continuous urban growths;compared to the typical Chinese cities of Xi'an of the similar developing level,Bangalore of India has longer commuting distance,lower share of the transit,larger commuting CO₂ emissions.These are because the dispersed and incompact urban sprawlings and more uses of the two wheelers fueled by gasoline,which is caused by the high market economic system and larger share of the low-income households in Bangalore of India.To realize the low carbon transport and urban development and to cope with the challenges of the increasing transport CO₂ emissions brought by the urban sprawls,population and economic growth,this thesis proposed the following strategies:???In the process of the rapid urbanization,motorization and city cluster development in Chinese and Indian cities,there exist unavoidable increases of the car availability and commuting distance.Thus,to slow down the much increase of the commuting CO₂ emissions,it is necessary to form polycentric urban patterns,to control the scale of mega cities,to develop industry,real-estate and transit facility simultaneously in the new town or satellite city,to restrict the car use,and to promote transit priority in the city cluster area.By these measures,the non-motorized traffic and transit can be used more frequently;commuting distance and commuting CO₂ emissions can be decreased.?ii?The key to reduce the commuting CO₂ emissions during the rapid urbanization,motorization and city clustering is to increase the vehicle occupancy and control the increase of the commuting distance.Thus,encouraging more transit uses,car sharing,and to form the job-housing banlances are the effective and important measures to mitigate the increases of the urban commuting CO₂ emissions.