中文摘要：

城市土地利用的空间结构是城市交通产生的根源。其中，城市规模、城市密度与城市蔓延、单中心与多中心、就业与居住的空间关系是影响城市通勤时耗的重要空间因素。城市规模越大，通勤时间越长。密度对通勤时耗的影响是双重的，一方面，紧凑型发展带来的各种活动空间范围的缩小有助于减少出行时间；另一方面，过度密集化又会带来拥堵，从而延长通勤时间。城市蔓延由于定义模糊性，其对通勤时耗的影响是不确定的。关于多中心城市结构是否有助于降低通勤时耗，研究结论分歧很大，导致结论分歧的一个可能的重要原因是，不同性质的多中心对通勤时耗的影响是不同的。职住平衡有助于减少通勤时耗得到多数研究的认可，但职住平衡是否能够实现却受到有力的质疑。

英文摘要：

Urban spatial structure impacts on urban traffic. Urban size, urban densi- ty, urban sprawl, monocentric and polycentric structure and the spatial relationship of jobs and housing are the important spatial factors that influence the urban com- muting duration. For example, the larger the city, the longer the average commut- ing time. But the influence of density to the commuting duration is more com- plex as compact development shortens average travel time while it also causes congestion. Because of its vague definition, the influence of urban sprawl to com- muting time is ambiguous. Furthermore, whether polycentric urban structure helps to reduce commuting time is still up to debate and one of the possible reasons that lead to different opinions may be due to the different nature of polycentric structures. Moreover, most researches agree that jobs-housing balance helps to re- duce commuting duration although deep skepticism exists about the feasibility of achieving balance.