Master of Science in Civil Engineering (MSCE)
Civil and Environmental Engineering
The objective of the research was to analyze the current practice of assigning capacity values to links of a network and to determine how capacity can be assigned more accurately without greatly increasing time, effort and costs. Currently in most planning networks, the link capacities are assigned based on the number of lanes and a gross facility and area type considerations (LSU, 1997). This practice might have affected the results of travel demand modeling performed using the network. To test this hypothesis, the current practice was compared to the practice of assigning capacities link-by-link using the Highway Capacity Manual (HCM) methodology. Significant differences were found in travel volumes, travel times, travel speeds and volume to capacity ratios, which resulted from travel demand modeling. It was therefore concluded that the current practice of assigning capacity values was not accurate because it affected the results of modeling. Calculating and assigning capacities link-by-link would involve time, effort and costs if all HCM adjustment factors were to be estimated. Therefore, the thesis attempted to determine if the effects of some or all adjustment factors could be ignored while assigning capacities link-by-link to reduce data collection effort. However, when the results of travel demand modeling with these capacity values was compared to corresponding results where capacity was calculated using all HCM adjustment factors, significant differences were observed. Therefore, the study failed to make any conclusions on whether the effects of adjustment factors could be ignored to reduce data collection effort, without greatly affecting the accuracy of modeling. The results of this study provided insights on how capacities could be assigned more accurately to links of a planning network. It could also provide insights to further studies on how data collection effort could be reduced for estimating and assigning capacity values to links.
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Dheenadayalu, Yogesh Kandaswamy, "Analysis of methods for assigning capacity in a transportation planning network" (2002). LSU Master's Theses. 656.