Intersection Gap Control for Simultaneous Straight and Left Turns
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Solution Overview
Problem
Traffic light intersections where vehicles driving straight and turning left are allowed to pass simultaneously are bottlenecks that reduce traffic flow density due to inefficient time gaps, leading to delays and increased fuel consumption and emissions.
Innovation Solution
The method involves using Car2X communication to transmit the number of waiting left-turning vehicles to equipped vehicles driving straight ahead, which adjust time gaps through automatic longitudinal control to create safety and limit time gaps, optimizing traffic flow by converting inefficient gaps to allow collision-free left turns without significantly affecting straight traffic flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vehicles maintain large safety distances at intersections, then collision risk is reduced, but traffic flow density decreases and fuel consumption increases
Solution Approach 1:
The system performs preliminary identification of suitable time gaps in the oncoming traffic flow before the left-turn vehicle attempts to turn. By pre-selecting and preparing to utilize identified suitable gaps, the system enables left-turning vehicles to proceed without maintaining excessive safety distances, thereby increasing traffic flow density while ensuring collision avoidance through advance planning and communication.
Solution Approach 2:
The system continuously monitors the oncoming traffic flow to identify suitable time gaps and provides feedback to left-turning vehicles about the availability and characteristics of these gaps. This feedback mechanism allows vehicles to adjust their turning timing and speed to utilize identified gaps efficiently, optimizing both safety and traffic flow density without requiring unnecessarily large safety distances.
2Reliability
If vehicles maintain large safety distances in oncoming traffic, then collision risk is reduced, but left-turn opportunities are lost and traffic efficiency decreases
Solution Approach 1:
The system identifies suitable time gaps in the oncoming traffic flow in advance before the left-turn vehicle needs to maneuver. By performing this identification preliminarily and communicating gap availability to left-turning vehicles, the system eliminates unnecessary waiting time while ensuring that vehicles only turn when suitable gaps are confirmed available, thus reducing left-turn delays without compromising collision avoidance.
Solution Approach 2:
The system acts as an intermediary between the oncoming traffic flow and left-turning vehicles by identifying and communicating suitable time gaps. This intermediary function enables left-turning vehicles to synchronize their maneuvers with identified gaps in oncoming traffic, reducing waiting time and improving traffic efficiency while maintaining collision avoidance through the mediation of gap information.
3Productivity
If equipped vehicles adjust time gaps to create limit gaps for left turns, then traffic flow density increases, but control system complexity increases
Solution Approach 1:
Equipped vehicles perform the adjustment of time gaps autonomously using their own automatic longitudinal control systems based on information about waiting left-turning vehicles. Rather than requiring external control infrastructure, each equipped vehicle independently adjusts its position and speed to create suitable limit gaps, thereby increasing traffic flow density without adding significant control system complexity to the overall intersection management.
Solution Approach 2:
The system changes the temporal parameters of traffic flow by adjusting the time gaps between equipped vehicles based on the number of waiting left-turning vehicles. By dynamically modifying these time gap parameters, the system creates limit gaps that enable left-turn maneuvers while maintaining overall traffic flow density, achieving improved productivity through simple parameter adjustment rather than complex control mechanisms.
Data Source
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AI summary
The present invention relates to a method for increasing the density of traffic flow at a signal-controlled intersection having a traffic-light sequence in which vehicles driving straight ahead and vehicles turning left may simultaneously pass through the signal-controlled intersection, wherein the vehicles driving straight ahead have priority in accordance with traffic regulations and are at least partially equipped vehicles which have Car2X communication, automatic longitudinal control and a control unit. In order to increase the density of traffic flow, the invention proposes that, first, the number of waiting, left-turning vehicles is transmitted, by means of the Car2X communication, to the equipped vehicles that are driving straight ahead. Subsequently, the time headways between the vehicles driving straight ahead are set by means of the control unit and the automatic longitudinal control in accordance with the number of left-turning vehicles so that a first portion of the time headways are safety time headways, each of which corresponding to the required safety distance, and the second portion of the time headways are critical gaps, which allow at least one left-turning vehicle to turn without a collision.