本文采用"Web of Science"数据库收录的1999-2013年期间发表的探讨时空关系相关文献,包括2263篇直接文献和这些文献引用的78139篇参考文献为基础数据,采用Histcite软件构建时空关系研究文献数据库,结合Citespace软件对该数据库进行文献引用关系和知识图谱的可视化处理,并对热点文献进行解读与分析,从而分析时空关系研究的研究热点和发展趋势。研究发现:2000年前后,时空关系研究与GIS结合逐步突破了传统时间地理学研究的技术瓶颈和研究框架,迅速进入了一个文献爆炸的阶段,研究的内容逐步从时空行为的描述转向对时空关系的解释。随着时空GIS技术的不断成熟,本领域的研究更多地把时空行为作为一种变量,对各种时空现象和社会问题进行解释,而不仅仅是一个被描述和解释的对象,其学科应用价值将逐步突显。
This paper reports the effects of using an "odd and even" traffic restriction policy in Beijing during the 2008 Olympic Games. Based on data from 529 traffic detectors on the expressway network and some main arterials in Beijing, China, a comparative analysis has been carried out on the following parameters: the total traffic volume within the expressway network, the total traffic volume on different ring expressways, the traffic volume and speed of a freeway segment, and an arterial street before and after the implementation of the traffic restriction policy. The results show that during the traffic restriction period, although more than 50% of vehicles were forbidden to travel in Beijing,the traffic volume was only reduced by 20%-40% while the travel speed had been increased by 10%-20%. This suggests that such traffic restriction policy may be an effective shortterm management measure in dealing with increased transportation demand and congestion during major events, such as the Olympic Games. Results also indicate that vehicle travel demand does not decrease with the same proportion as the total vehicles forbidden, at least for the expressway and main arterials in a city.
