英文摘要 |
The characteristics of motorbike discharge behaviors are very importantfor the analysis of the capacity of exclusive motorbike lanes. However, previousresearches disregarded the influences of different separation types (i.e. roadmarking or physical separation) and did not illustrate the methods of measuringlane-width, and the numbers of sampling cycles as well. The findings in previousstudies were inconsistent and impractical. This study collected field data usingcameras at eight sites with lane-widths ranging from 1.7 to 3.4 meters in Taipeicity, with more than 50 cycles at each site. Researchers recorded the horizontalpositions of back-wheels of motorbikes passing the reference line, which wasidentified as a stop line, and determined the actual discharge-width by anα-percentage cutting rule. In the meantime, the numbers of discharged motorbikeswere counted every 2 seconds. The findings of this study were summarizedas follows. (1) The value of α was 0.05 because the corresponding actual discharge-width could be effective in estimating saturation flow rates. The actualdischarge widths at these eight sites ranged from 1.3 to 3.4 meters. (2) The dischargerates became stable 10 seconds after green light turned on. It showedthat the saturation flow rate exists. (3) It was found that the saturation flowrates clearly increased when the available lane widths widened. (4) Based on theavailable lane-width (W, meters) and the corresponding saturation flow rate (S,motorbikes/hr), a simple regression model was estimated as S = 6168.6 +441.9W2. The coefficient of determination (R2) was 0.90 with all estimated parametersbeing statistically significant. Furthermore, this study estimated thecapacities under various green intervals based on the estimated saturation flowrates. The results of this study are essential for setting up exclusive motorbikelanes in the future. |