Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 95 for “"Headway"”.
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Automatic Ultrasonic Headway Control for a Scaled Robotic Car
… concerned with the development of an automatic headway control system that utilized ultrasonic sensors. This control system was intended to automatically maintain headway distance in an effort to create an adaptive cruise control system for this scale model vehicle. Implementation of such …
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Time Headway and Platooning Characteristics of Vehicles on Interstate Highways
Mean time headway for platooning vehicles decreased as traffic volume increased. About 18% to 31% of platooning vehicles had a space gap that corresponds to a reaction time of 0.5 second or less, with more than half of these in large platoon of 5 vehicles or more. About 15% to 85% of platooning …
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Optimization of headway, stops, and time points considering stochastic bus arrivals
… cause extra wait time to passengers because of headway irregularity at stops, as well as extra recovery time built into schedule and additional cost to operators because of ineffective utilization of allocated resources. This study aims to optimize service planning and improve reliability for a …
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Development of automatic vehicle headway control law and a simulation tool
… tool for the study of automatic vehicle headway control. This research considers longitudinal control of a platoon of vehicles on automated highways. A new way of designing control law for vehicle following is presented by introducing safe boundary concept - the trail vehicle should never …
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System Dynamics Model for Testing and Evaluating Automatic Headway Control Models for Trucks Operating on Rural Highways
… AVCS technologies, and, in particular, automatic headway control models for trucks operating on rural highways. The emphasis is put on the realization of vehicle headway control in the real world highway systems. System dynamics has been selected as the simulation tool for developing, testing and …
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Towards 3-minutes : application of holding and crew interventions to improve service regularity on a high frequency rail transit line
… operations. This thesis explores aspects of headway and dwell time regularity and their impact on service provision on the MBTA Red Line, with specific reference to the agency's objective of operating a future 3-minute trunk headway, and to issues of service irregularity faced today. Current …
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On Statistical Analysis of Vehicle Time-Headways Using Mixed Distribution Models
For decades, vehicle time-headway distribution models have been studied by many researchers and traffic engineers. A good time-headway model can be beneficial to traffic studies and management in many aspects; e.g. with a better understanding of road traffic patterns and road user behaviour, the …
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Improving high-frequency transit reliability : a case study of the MBTA Green Line through simulation and field experiments of real-time control strategies
… behavior. This variability leads to irregular headways, resulting in longer passenger waits and decreased effective capacity as gaps in service form. Real-time control strategies allow controllers to intervene at terminals and en route to regulate headways and improve performance. This research …
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Improving the transfer experience at intermodal transit stations through innovative dispatch strategies
… of a bus hold light system that is based on headways of arriving trains in an effort to improve rail-to-bus transfer connectivity through a simple-to-implement, low-cost dispatching strategy. An analytical model and a simulation model are developed to analyze the impacts of the proposed …
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Intelligent Cruise Control System Impact Analysis
… safety by assisting drivers in maintaining safe headways. This thesis explores this potential through comparisons of ICC to conventional cruise control (CCC) and manual driving. Accordingly, descriptions are given of both CCC and ICC systems. Furthermore, descriptions of ICC evaluation studies …
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Improving transit service connectivity : the application of operations planning and operations control strategies
… Route 53 were not significant mainly due to the headway compatibility requirement which reduces the number of transfers amenable for improvement. Greater benefits were encountered when the schedules on the connecting routes were allowed to change as well. For Route 63, schedule coordination is …
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Simulating service reliability of a high frequency bus route using automatically collected data
… provided to passengers. Since they have short headways and high passenger demand interaction between buses can easily develop, causing degradation in service reliability. This, in turn, can prompt service interventions to correct service reliability. Transit agencies are implementing new …
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Estimation of run times in a freight rail transportation network
… meets, passes, overtakes, direction, arrival headway, and departure headway to predict train run times. The performance of the proposed regression model is compared against a baseline simple historical averaging technique for a two year period of actual train operational data. The proposed …
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Modeling drivers' acceleration and lane changing behavior
… A probabilistic model, that is based on a time headway threshold, is used to determine the regime the driver belongs to. Heterogeneity across drivers is captured through the headway threshold and reaction time distributions. The parameters of the car-following and free-flow acceleration models …
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Design of Switching Strategy for Adaptive Cruise Control Under String Stability Constraints
… chart to illustrate the relationship between headway distance and velocity difference, and then find out a constant deceleration trajectory on the chart, which the following vehicle is controlled to follow. This control strategy has a shorter elapsed time than existing ones while still …
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A Simulator-Based Investigation of Visual, Auditory, and Mixed-Modality Display of Vehicle Dynamic State Information to Commercial Motor Vehicle Operators
… two vehicle speeds, and two levels of headway. Accident occurrence was measured for impending side collision scenarios under two vehicle speeds, two levels of visual workload, two auditory displays, absence/presence of mirrors, and absence/presence of dash-mounted iconic display. …
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Evaluation of bus priority strategies for BRT operations
… that consider different conditions such as headway, loads, and traffic demand in a BRT context. Results for both case studies support the belief that TSP can provide travel time reductions for transit vehicles, together with reductions in headway variability. However, results proved to be …
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Behavioural adaption of drivers of unequipped vehicles to short time headways observed in a vehicle platoon
… traffic and are designed to maintain small headways in order to have a beneficial effect on both energy consumption and traffic flow. The overarching aim of this work was to investigate whether the presence of automated vehicle platoons will impact UVDs’ car-following behaviour. This …
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Development of a methodology for measuring delay-based passenger car equivalent for heavy vehicles at signalized intersections
… at signalized intersections are based on headway concepts, and are mainly focused on adjusting the ideal saturation flow rate. They do not reflect the total effect of heavy vehicles on delay. The constant PCE value, which is independent of traffic volume and percentage of heavy vehicles, …
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Analysis and prediction of traffic accidents at urban intersections
… traffic parameters, namely standstill distance, headway duration, and following distance oscillation, on both traffic flow and intersection safety. A data-driven approach is proposed for identifying the Pareto optimal sets of parameter combinations that both maximise the flow volume and minimise …
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