Intersection Stage Green-Time Allocation Using Saturation Flow Ratios
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Solution Overview
Problem
Traditional signal control time assignment strategies for intersections fail to account for the impact of saturation flows, leading to inaccurate optimization of green light times and inefficient traffic management.
Innovation Solution
A method that considers flow direction flow rate ratios and adjustment coefficients based on lane evaluation indicators and configuration data to optimize green light times, using a critical flow direction with the largest flow rate ratio to improve the accuracy of stage green signal ratios and signal control time assignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional signal control time assignment strategy is used based solely on flow rate ratios from lane stop lines, then the control system is simple, but the accuracy of green light time optimization deteriorates due to ignoring saturation flow impacts
Solution Approach 1:
The patent segments the flow direction evaluation into multiple components: flow rate ratio calculation from lane stop line detectors, saturation flow assessment from lane departure line detectors, and critical flow direction identification. This segmentation allows precise optimization by considering both flow rate ratios and saturation flows separately before integrating them into the green light time assignment.
Solution Approach 2:
The patent introduces an intermediary calculation layer that computes flow direction adjustment coefficients based on saturation flows. These coefficients act as mediators between the raw detector data and the final green light time optimization, translating saturation flow information into adjustment factors that modify the green light time assignment.
2Measurement precision
If green light time optimization considers both flow rate ratios and saturation flows, then the accuracy of stage green signal ratio calculation improves, but the computational complexity increases
Solution Approach 1:
The patent performs preliminary calculations by first determining flow direction adjustment coefficients based on saturation flows before calculating the final stage green signal ratio. This preliminary action separates the complex saturation flow analysis from the final optimization calculation, making the overall process more manageable and systematic.
Solution Approach 2:
The patent changes the parameters used in the calculation by introducing flow direction adjustment coefficients that incorporate saturation flow information. Instead of using only flow rate ratios, the system transforms the parameters to include both flow rate ratio and saturation flow components, thereby improving accuracy while maintaining computational feasibility through structured parameter transformation.
3Measurement precision
If the critical flow direction with largest flow rate ratio is used for optimization, then the green light time allocation becomes more accurate, but the system requires more comprehensive detector coverage
Solution Approach 1:
The patent segments the detector requirements into functional groups: lane stop line detectors for flow rate ratio measurement and lane departure line detectors for saturation flow measurement. This segmentation allows the system to achieve accurate flow direction evaluation by strategically placing detectors in specific locations without requiring comprehensive coverage of all possible measurement points.
Solution Approach 2:
The patent applies local quality by focusing detector coverage on critical locations where flow rate ratios and saturation flows are most influential. Instead of uniform detector placement throughout the intersection, the system concentrates detection capabilities at key positions (lane stop lines and lane departure lines) where they provide maximum information value for identifying critical flow directions.
Data Source
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AI summary
The embodiments of the present application provide a method and a device for optimizing green light time of an intersection for a stage, an apparatus equipment and a storage medium. The method includes: obtaining flow direction flow rate ratios and flow direction adjustment coefficients of flow directions of an intersection based on lane evaluation indicators and lane configuration data of lanes of the intersection, wherein the flow direction adjustment coefficient of each of the flow directions changes positively with a saturation level of that flow direction; obtaining stage flow rate ratio for each of stages based on a product of the flow direction flow rate ratio and the flow direction adjustment coefficient of a critical flow direction of the intersection for that stage, and obtaining a stage green signal ratio of each of the stages based on the stage flow rate ratios for the stages, wherein the critical flow direction for each of the stages is a flow direction with the largest flow direction flow rate ratio in that stage; and optimizing green light times of the intersection for the stages based on the stage green signal ratios for the stages and signal control configuration parameters. The technical solutions of the present application obtain the stage flow rate ratios based on the critical flow direction of each stage, and then obtain the stage green signal ratios, so that the stage green signal ratio is more accurate and the effect of the optimized signal control timing scheme is improved.