Research On The Characteristic Of Volume Variation Per Hour In The Urban Central Area

The urban central area is the core of urban area, but is also a zone which contains huge traffic jams. As one of important indicators to the traffic situation in the central urban area, the characteristic of volume variation per hour contains a wealth of traffic information and has temporal and spatial correlation, the results varies when observation on different dates or sites and so on. It is helpful for us to understand the correlation between temporal and spatial and monitor traffic conditions by summary of the characteristic of volume variation per hour, Therefore, it is very necessary to analyze the characteristic of volume variation per hour.The expression types and time distribution of traffic volume are introduced firstly in this paper, and then the author defines similarity coefficients and volatility as the measure tools for the characteristic of volume variation per hour and explains the rule of similarity and several factors which influence its judgment of similarity. Based on the definition and explanation of similarity, the author confirms the similarity of characteristic of volume variation per hour between different weekdays in one month in central urban area, the difference of the characteristic in one year and the volatility of traffic hour volume are also discussed. On the research result of one typical intersection, the characteristic of volume per hour between the different sections on the same artery, the different arteries, areas and intersection types are also studied. Finally based on the conclusions above, the author analysis the characteristic of volume variation per hour on holiday, including weekends and special holiday such as Spring Festival. Research findings and conclusions include:1. The characteristic of volume variation per hour is similar between weekdays in one same month. In one year, however, the characteristic is different, especially on the morning peak hour. The two time section (April to September and October to March in the next year) shows different characteristics and the most volatile volume also concentrates in the morning peak hours.2. The degree of similarity of intersections along the same artery decreases by the distance between intersections increases, but the trends is not totally consistent. Influenced by the traffic situation of high-grade road which cross with the artery, the characteristics of intersections which belong to different road sections usually varies from each other.3. The similarity of volume variation per hour between different arteries and areas are related to the distance from the intersection site and the city center. These differences mainly manifested in the morning peak hour flow ratio, duration and start times. Where the distance between the intersection and the city center is short, it means the lower the peak hour flow ratio, the longer the duration of the peak period and the late start time.4. The characteristics of volume variation per hour on weekends are stable, which means no significant changes within one year. The difference of characteristic between different intersections mainly focus on the time section from 12:00 to 18:00, and also there are different types of characteristic in different areas, according to the different flow curves, the author divide the types into four different groups: the type of evening peak, the type of morning peak, the type of saddle and ladder type.5. There is no huge difference between weekend and special holiday( Spring Festival, Labor Day and National Day), and the special holiday has no impact on the week before or after it.