Functional Reliability Quantitative Analysis And Application Of City Trunck Roads Based On Probability Measures

Expressway and arterial road is artery of the urban traffic, collectively known as the urban trunk roads, bearing a greater proportion of urban traffic. "Urban Road Engineering Design Code"(CJJ37-2012) defined the function of urban roads in each grade, that expressway traffic should achieve a continuous passage, and arterial road should be connected to all major cities partition, taking traffic function as the main function. For the analysis of actual operating state of urban trunk, should take realization degree of its planning and design functions as the main index to determine the reasonableness of the road planning and design achievements. Taking into account the state of the traffic flow time variation, the characteristic index of realization degree of the urban trunk functional is a variable, so we need to use probability measure method. In summary, funded by the National Natural Science Foundation project ".Based on functional analysis of a phased program of urban road traffic and Decision"(item No. 51278468), this paper studies the urban trunk function reliability quantification methods based on probability measure. Compared with the service level, functional reliability quantifies the finish level of road function, without having to give a clear cut-off point, which is more helpful for traffic managers to make judgments and decisions.First of all, this paper studies the specific functional description of expressway and arterial road respectively, and has given the appropriate functional characterization indexes. Expressway function mainly reflects in speedy passage and continuous running two aspects. Their characterization indexes were identified as driving speed and headway variation coefficient. Arterial road function embodies mainly carrying larger traffic volume, higher running speeds and services in medium and long distance running, and their characterization indexes are identified as traffic,travel speed and straight rate.Secondly, combining reliability theory, we propose the concept of expressway functional reliability and arterial road functional reliability, taking them as probability measure indexes for quantitative evaluation the realization degree of urbanexpressway and arterial road functions. Then this paper builds appropriate expression of the mathematical model of expressway function reliability and arterial road function reliability. In the assumption of each characteristic index is independent, the degradation formula of expressway function reliability and arterial road reliability has been got.Finally, we design the survey program and collect field video data, combined with statistical analysis software SPSS PALISADE to examine the irrelevant between each characterization index, as the requirement of independent of each index. We use functional reliability formula before and after degeneration to calculate functional reliability of each survey road section. Their results are basically tallies, which valid proofs the assumption of the independent between each characterization index. Then we separately evaluate LOS of each expressway basic section and arterial road intersection. Its analysis results and functional reliability evaluation results have achieved mutual authentication, suggesting the rationality and feasibility of the proposed method in this paper.