Research On Grade Proportion And Layout Method Of Urban Road

There are many representations about road function and administrative levels at present. And the voice of obscure road function and unreasonable network grade proportion is also high. But there are few researches on grade proportion and micro layout of urban road, which guarantees road function. It is chiefly focused on road grade proportion configuring and micro layout (such as road density, space and cross type).Firstly, studies on road grade proportion at domestic and abroad are reviewed and the shortage is analyzed. After discussing recommendable value in urban road transportation planning and designing standard and analyzing branch road concept generally,leading content, research lay, administrative levels and goal are given. Secondly, it is emphasized at road function, and different concept in both wide sense and narrow sense. Road function is the cut-in point of my research, so it is important to look for measurable indexes, which can distinguish those different road functions. Going without saying, Vehicle Trip Distance (VTD) is the most feasible because it can be gotten by survey. Resident trip distance can be converted to Vehicle Trip Distance. The first core problem is the characteristic of VTD. Through reasonable hypotheses, it proves that VTD is submitted to Rayleigh Distribution. Then, it fits parameters by 11 cities'dates and gets good results. Furthermore, it analyzes influencing factors,such as urban land scale, urban figure and transportation system mode, and establishes regression nonlinear model to confirm the only parameter. Average trip distance can be calculated by Rayleigh Distribution.Preponderant trip distance and transportation turnover investigation for each road grade are the second core problem. In preponderant trip distance study, it supposes that every trip distance in the same orientation in the same road grade should not exceed the space between two proximate higher road, and that every trip route should be from lower road grade to higher road grade and then from higher road grade to lower road grade, and so on. Based on VTD distributing function and preponderant trip distance, road transportation turnover formula can be easily obtained.Because it is facile to get road transportation turnover, every grade road length and proportions can be confirmed by the equilibrium thought about supply and demand. This is the third core problem. But, there is an inconsistency between pre-setting space value in preponderant trip distance study and relatively reasonable space value by front research. That is the difficulty in this core problem. The name trip distance-turnover is concluded, through which, commending values are given based on 1km/km2 artery...