空气重度污染期间城市交通运行特征分析

近年来中国重度污染天气频发，严重影响居民生产生活。由于缺乏空气重度污染期间居民出行行为方面的分析，难以量化城市交通运行特征的变化。以北京市两次空气重度污染红色预警实践为契机，全面收集红色预警期间道路交通运行监测数据、交通排放、居民出行行为等多元数据，通过历史数据对比和交叉分析，得到空气重度污染期间居民出行需求、出行方式、出行时间等出行行为特征，以及道路交通量、运行速度等指标变化。结果显示：空气重度污染期间居民出行特征变化较大，需求降低、方式转移多元、出发时间集中；实施机动车单双号限行措施后，机动车日均氮氧化物(NOX)排放量减少19%，颗粒物(PM)排放量降低17%。

Urban Traffic under Severe Air Pollution

Recently, the frequent severe air pollution occurrences in China has made huge impact on daily life of urban dwellers. Due to the insufficient studies on residents' travel behavior during severe air pollu-tion, it is difficult to quantify the changes of urban traffic characteristics. Using the data collected during the two most severe air pollution events, such as traffic volume, level of pollution and residents travel be-havior, a study was conducted to investigate the changes in travel demand, travel mode choice and travel time as well as traffic flow and operating speed through cross-sectional and longitudinal data analysis. The results show that residents' travel characteristics altered significantly evidenced by lower travel demand, travel mode shift and more concentrated trip departure time under severe air pollution. With the road ac-cess restriction by even and odd license plate numbers, the daily vehicle emission of nitric oxide (NOX) and particulate matters (PM) were reduced by 19%and 17%respectively.