Research On Two-Lane Highway Capacity On Moutainous Areas

The territory of our country is very vast, 69% of it is the mountainous area. Especially in 12 western provinces and cities, the proportion of mountainous areas is up to more than 80%. As main highway form in our country, the two-lane highway is very universal in road network. In west areas, the two-lane highway accounts for more than 95% of the total length, which plays a great role in the road network.With the deep development of western regions, the transportation construction is regarded as the most important thing in the development of western regions by the central authorities, and will be invested 700 billion yuan to improve the western highway network and to solve the badly driving condition and the low level of attainability. It is one foundational work of large-scale construction and enormous investment. The departments of the highway design must be required to make decision according to the indexes, such as rational highway capacity, level of service and road alignments, etc. If not, the huge wasting and back-end ecocatastrophe will be brought. But the research of two-lane highway capacity in our country, especially the study on mountainous areas has already lagged behind engineering practice. It couldn't meet the request for extensive road construction of the west area at present, so the research of two-lane highway capacity on mountainous areas is set up by the Ministry of Communications specially.The domestic and international study on two-lane highway capacity is summarized and commented at first in the dissertation, especially American study history and conclusion in the Highway Capacity Manual (HCM) in detail is analyzed, and our researches'achievements on two-lane highway capacity are reviewed and outlined. Based on this, an interesting problem is proposed that the capacity of both directions is smaller than twice as this of one direction on two-lane highway. And the deficiencies are pointed out in present researches, such as highway capacity, level-of-service, influence factor of road alignments, etc. From these, it has confirmed that the thesis should be studied from rational analysis, quantitative analysis of level-of-service, impact on capacity of road alignments, setting-up simulation model, etc.The high-accuracy GPS dynamic data acquisition appearance is proposed to be used for the first time to carry on the experiment of overtaking on two-lane highways, and experiment scheme is designed according to the driver's perceive to judge each overtaking course. Based on the experiment data, it can get two important parameters of acceptant gap– the critical gap of overtakable time headway and returnable time headway through data processing, which can offer the strong support to the research of two-lane highway capacity with qualitative and quantitative analysis. Besides, the experiment methods is provided to observe overtaking ratio and to measure the...