01337206

Component

https://doi.org/10.3141/2259-09

http://scholar.google.com...oyce&publication_year=2011

One critical issue of traffic control is the optimization of signalized intersections for improved multimodal safety and operations. Accommodating pedestrian traffic at intersections is challenging because the demands of multimodal service compete fiercely on limited green time resources. The "Highway Capacity Manual" prescribes that the parallel vehicle green must exceed “Walk” plus pedestrian clearance interval (PCI) timed by a design walking speed. This static PCI timing is unsafe because seniors and children are likely to be slower than the design pedestrian. Furthermore, a vehicle-flow issue arises when the prolonged PCI exceeds the operationally efficient parallel green: additional vehicle right-of-way, unnecessary for operational efficiency, preempts green time from conflicting phase(s) and increases intersectionwide queuing delays. Queuing delays necessitate a trade-off between competing multifaceted traveler needs. Fuzzy logic control (FLC) proves effective, flexible, and robust in handling competing objectives. With the dynamic PCI concept, this research developed an intelligent traffic signal system that performed friendly pedestrian accommodation and also incorporated FLC into fulfilling multifaceted vehicle needs. The potential benefits from the new system optimized with a genetic algorithm were quantified through a comparison with a standard dual-ring, eight-phase, vehicle-actuated controller, conventionally cited as NEMA (National Electrical Manufacturers Association) control. Microsimulation experiments revealed that the current countermeasure, which lowered PCI timing design speed to strengthen crossing safety, was operationally deficient. The existing timing standard cannot offer adequate safety for all pedestrians, and the NEMA system omits multifaceted vehicle needs in control logic. In contrast, the FLC system fully protects all pedestrians through dynamic PCI and smartly serves manifold vehicle needs well. The FLC system outperforms the NEMA control by embodying a reasonable trade-off between competing objectives in the management of an isolated intersection.

01364838

11-0848

English

pp 96-111

2011

Transportation Research Record: Journal of the Transportation Research Board

9780309222952

Print

Figures (6) ; References (45) ; Tables (5)

Advanced traffic management systems; Fuzzy controllers; Fuzzy logic; Genetic algorithms; Green interval (Traffic signal cycle); Isolated intersections; Optimization; Pedestrian clearance interval (Traffic signals); Pedestrian safety; Pedestrian traffic; Signalized intersections; Traffic queuing

Intelligent traffic signals

Highways; Operations and Traffic Management; Pedestrians and Bicyclists; I73: Traffic Control

TRIS, TRB

Feb 17 2011 5:36PM

• Analysis of Peer Data on Intersections for Decisions About Coordination of Arterial Traffic Signal
• Automated Intersection Control: Performance of Future Innovation Versus Current Traffic Signal Control
• Comparison of Alternative Real-Time Performance Measures for Measuring Signal Phase Utilization and Identifying Oversaturation
• Computational Efficiency of Alternative Algorithms for Arterial Offset Optimization
• Design of Intergreen Times Based on Safety Reliability
• Detection of Stop Bar Traffic Flow State
• Detection Performance of Wireless Magnetometers at Signalized Intersection and Railroad Grade Crossing Under Various Weather Conditions
• Development and Evaluation of Optimal Arterial Control Strategies for Oversaturated Conditions
• Estimating Signalized Intersection Delays to Transit Vehicles: Using Archived Data from Automatic Vehicle Location and Passenger Counting Systems
• Evaluating Robustness of Signal Timings for Varying Traffic Flows
• Heuristic Algorithm for Priority Traffic Signal Control
• Heuristic Approach for Estimating Arterial Signal Phases and Progression Quality from Vehicle Arrival Data
• Improving Safety and Mobility at High-Speed Intersections with Innovations in Sensor Technology
• Integrated Control of Freeway Interchange Model Based on Enhanced Cell Transmission Model
• Modeling Variability of Urban Travel Times by Analyzing Delay Distribution for Multiple Signalized Intersections
• New Evidence of Improvements in Dilemma Zone Protection by Detection-Control System
• Predictive Priority for Light Rail Transit: University Light Rail Line in Salt Lake County, Utah
• Quantifying Dynamic Factors Contributing to Dilemma Zone at High-Speed Signalized Intersections
• Quantifying the Benefit of Retiming Traffic Signals Through Multiple Regression
• Reliability, Flexibility, and Environmental Impact of Alternative Objective Functions for Arterial Offset Optimization
• Traffic Signal Optimization with Application of Transit Signal Priority to an Isolated Intersection
• Turn Pocket Blockage and Spillback Models: Applications for Signal Timing and Capacity Analysis
• Visual Education Tools to Illustrate Coordinated System Operation