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Consideration of 24-hour volumes in the selection of traffic signal control strategies for isolated intersections
Recent Doctoral Dissertations Consideration of 24-hour volumes in the selection of traffic signal control strategies for isolated intersections. Lee, Stephen Ching-Yung, Ph.D. University of Kansas, 1993. 169 pp. Order Number DA94-05758 Selection of the most appropriate traffic signal control strategy for an isolated intersection is a difficult and complicated process. This research utilized TRAF-NETSIM to evaluate the operational performance of an isolated intersection under the control of pretimed, semi-actuated and actuated controllers for continuous 24-hour traffic volumes. Guidelines were developed for the selection of the most effective traffic signal control strategy. Evaluations of the effects of the flashing operation of a traffic signal during the night and advanced pretimed controllers with the capability of providing more than 3 timing plans on the operational performance of an isolated intersection were also performed. The findings of this research include: ( 1) The delay and stop Measures of Effectiveness (MOE) factors are appropriate for evaluation of the operational performance of an isolated intersection. (2) Either the pretimed or actuated control is the most effective traffic signal control strategy for isolated intersections without the flashing operation during the night for the 24-hour and peak &hour traffic volumes. The conventional 3-dial pretimed controller is still a valuable control strategy and should not be eliminated from consideration. (3) The most effective control strategy for the peak 8-hour operation of an isolated intersection is most likely also the most effective one for overall 24-hour operation. (4) A combination of pretimed, actuated and semi-actuated control, without the flashing operation during the night, is the most effective traffic signal control strategy for the 24-hour and peak &hour traffic volumes. (5) The flashing operation (i.e., flashing yellow and red on the major and side streets, respectively) of a traffic signal during the night can reduce the intersection delay and stop time significantly and provide better operational performance. (6) Advanced pretimed controllers are generally more effective than conventional 3-dial pretimed controllers. Although the reduction in total delay and stop time between the 3-, 12- and 24-dial pretimed controllers are not statistically significant, the reduction in the total delay and stop time for the advanced pretimed controllers will be substantial considering the total 24-hour traffic volumes using the intersections. (7) There is no direct, universal method to determine the most effective combined traffic signal control strategy for isolated intersections.
Critical assessment of the features of two ramp metering optimization models. Park, Eunmi,
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Ph.D. Texas A&M University, 1993. 263 pp. Chair: Carroll J. Messer. Order Number DA94-10845 In this dissertation, two ramp control models used for freeway traffic management, FREQ and S971, are critically reviewed. FREQ was developed at the University of California, Berkeley and S971 is being developed at the Texas Transportation Institute, Texas A&M University. Assessments were conducted using a macroscopic simulation program, FREFLO, which is supported by the Federal Highway Administration. Other tools, including LINDO and SAS, were used to assess the models. Based on the assessment results, new features for S971 were developed to adapt the model to the constrained operational conditions that may exist in a freeway corridor during congested traffic conditions. The study results showed that S971 is preferable to the FREQ model in view of its theoretical basis of modeling and its simulated traffic performance. A user-friendly software version and program manual, as available with the FREQ model, are needed to encourage wide acceptance of the S971 model. In developing the procedure for selecting the pm (i.e., the fraction of traffic in the merge lane) factor used in the S971 model, a new concept for freeway lane equilibrium in the merging area was introduced into freeway ramp control for corridors in constrained operational conditions. This concept states that the system tends to equilibrate and adjust itself toward system optimum. An equation derived for estimating the equilibrium pm was recommended as the best selection and an algorithm for the S971 model was designed as a part of a real-time freeway control system. To provide the S971 model with adaptability to non-steady state freeway conditions, a self-calibration algorithm for the S971 model was developed for queueing conditions that may exist in a freeway corridor. By taking advantage of information available on freeway link volumes, the proportion of vehicles in each freeway section entering from the on-ramps is adjusted for queueing conditions from which freeway link volumes can be better estimated. The capability of the algorithm was illustrated and tested within a limited scope of study.
EASINET: A procedural package for development and analysis of intersection control strategies. Malek, Shahram, Ph.D. Georgia Institute of Technology, 1992. 339 pp. Director: Peter S. Parsonson. Order Number DA93-15893 The purpose of this research was to investigate and develop a comprehensive tool to assist traffic engineers in the development and analysis of intersection
Critical assessment of the features of two ramp metering optimization models. Park, Eunmi,
71
Ph.D. Texas A&M University, 1993. 263 pp. Chair: Carroll J. Messer. Order Number DA94-10845 In this dissertation, two ramp control models used for freeway traffic management, FREQ and S971, are critically reviewed. FREQ was developed at the University of California, Berkeley and S971 is being developed at the Texas Transportation Institute, Texas A&M University. Assessments were conducted using a macroscopic simulation program, FREFLO, which is supported by the Federal Highway Administration. Other tools, including LINDO and SAS, were used to assess the models. Based on the assessment results, new features for S971 were developed to adapt the model to the constrained operational conditions that may exist in a freeway corridor during congested traffic conditions. The study results showed that S971 is preferable to the FREQ model in view of its theoretical basis of modeling and its simulated traffic performance. A user-friendly software version and program manual, as available with the FREQ model, are needed to encourage wide acceptance of the S971 model. In developing the procedure for selecting the pm (i.e., the fraction of traffic in the merge lane) factor used in the S971 model, a new concept for freeway lane equilibrium in the merging area was introduced into freeway ramp control for corridors in constrained operational conditions. This concept states that the system tends to equilibrate and adjust itself toward system optimum. An equation derived for estimating the equilibrium pm was recommended as the best selection and an algorithm for the S971 model was designed as a part of a real-time freeway control system. To provide the S971 model with adaptability to non-steady state freeway conditions, a self-calibration algorithm for the S971 model was developed for queueing conditions that may exist in a freeway corridor. By taking advantage of information available on freeway link volumes, the proportion of vehicles in each freeway section entering from the on-ramps is adjusted for queueing conditions from which freeway link volumes can be better estimated. The capability of the algorithm was illustrated and tested within a limited scope of study.
EASINET: A procedural package for development and analysis of intersection control strategies. Malek, Shahram, Ph.D. Georgia Institute of Technology, 1992. 339 pp. Director: Peter S. Parsonson. Order Number DA93-15893 The purpose of this research was to investigate and develop a comprehensive tool to assist traffic engineers in the development and analysis of intersection