| Summary: | 碩士 === 中央警察大學 === 交通管理研究所 === 104 === According to the Directorate General of Highways’s information, the mileage of Provincial highway without Expressway in Taiwan is about 3,460 kilometers, and rural two-lane highway is about 40% of it. However, the characteristics of traffic flow, especially on upgrade and curve segments on rural two-lane highway are lack of understanding. According to the Institute of Transportation’s research and literature reviews, it appears that the traffic flow characteristics on rural two-lane highway upgrade segments are much different from those on level terrain, in other words, grade, length of grade, length and radius of curvature, and percentage of heavy vehicles will contribute to the speed reduction. In chapter 12 of 2011 Taiwan Highway Capacity Manual, the analysis methodology of rural two-lane highway is to convert the demand volume into the demand flow under equivalent passenger cars by the percentage of heavy vehicles, adjustment for lane width, right-side lateral clearance, and passenger car equivalent (PCE) etc. However, the PCE in 2011 Taiwan HCM does not considerate the effect of grade, length of grade and percentage of heavy vehicle on upgrade segments so that the results of the analysis often can not reflect the actual level of service. To address this problem, in this research we applied the Traffic‐on‐Grade Simulation (TGS-2L) model, developed by the Institute of Transportation, to simulate the traffic condition on rural two-lane highway. Based on the results of the simulation, we found that the speed decreased with the increase of grade, length of grade, but the extent of speed reduction is effected on the climbing performance of vehicles types. In addition, on the segments which are allowed of passing, we supposed that there are all of passenger cars on the traffic flow. The speed is decreases with the increases of demand volume and grade. To conclude, when analyzing the traffic flow characteristics on upgrade segments, we suggest using TGS-2L model to simulate and estimate capacity or level of service, and take the Taipei-Ilan highway as an example of practical application.
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