Development of entrance ramp merging density model based on an urban expressway traffic condition

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Date
2007
Authors
Adnan, Muhammad Akram
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Abstract
Entrance ramp merging operation has significant impacts on expressway traffic operations and ramp junction geometric design. To date no research work has been conducted to assess the operational performance based on local entrance ramp expressway traffic condition. The current entrance ramp operational analysis methodology and models in the HCM 2000 are calibrated based on the United States (US) highway and traffic conditions. The application of the HCM needs to be justified for use in this country due to the fundamentally differences in driving habits, traffic composition and design configuration. Proper application of the models is crucial in order to ensure that the future designs of expressways are safe, efficient and economical where the issues of under-design or over-design of expressway will not occur. Also, the Malaysian guidelines and standard as in the Arahan Teknik Jalan: Interchange Design 1987 is out of date, which is based on the US HCM 1985 and the methodology approach and measure of effectiveness are totally different from the current HCM 2000 edition. Therefore a well-established empirical study had been implemented to calibrate entrance ramp merging models that are based on an urban entrance ramp expressway traffic condition in Malaysia. Two models were successfully developed in these studies that are needed in order to determine the Level of Service at entrance ramp merge junction. The first model is for estimating flow rates in lane 1 and 2 immediately upstream of the merge influence area and the second model is for prediction of density in merge influence area at entrance ramp junction. Sensitivity analysis had also been performed in order to measure how sensitive each of the predictor parameters for the two models. The development of the entrance ramp level of service estimation chart provides a valuable tool to be used by practitioners. Several graphs were created based on the models developed. Application example of using the chart had been demonstrated. As a result, traffic engineer and highway planner can use the developed chart in order to evaluate the existing entrance ramp expressway facilities Level of Service in an effective and systematic manner.
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PhD
Keywords
science mathematics , entrance ramp , density model , urban expressway , traffic condition
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