Measurement Time Interval (MTI) is crucial to obtain stable traffic flow parameters, such as volume, density and speed. And then credible relationships among these parameters as well as reasonable capacity are also dependent on appropriate MTI. Nevertheless, MTI has always been neglected in thepast researches of pedestrian traffic. Up to now there is still no consistent MTI standard which could be accepted universally. Different MTI results in weak comparability among numerous studies on pedestrian traffic parameters relationships. Some conclusions derived from unsuitable MTI are notreasonable. This paper takes pedestrian traffic in Shanghai Metro stations as observation context. By video recording, pedestrian traffic parameters, including volume and density are extracted manually through recording tapes using initial 5-second MTI for level passageway, ascending stairway, descending stairway and two-way stairway. Taking 5 seconds as basic incremental unit, traffic parameters for 10-second MTI, 15-second MTI and other analogical MTI values can be acquired in sequence. Based on the principlesof MTI selecting, appropriate MTI is determined by comparing the influence on stability of hourly flow rate and alterability of pedestrian gathering status when applying different MTI values. It is revealed that 30-secondMTI is optimal for all the observed facilities. From analysis on optimal MTI, it can be also inferred that traffic stability of level passageway ishigher than that of stairways, and one-way stairway is more stable than two-way stairway.
Abstract