Urban Overhead Road Off-Ramp Setting And Control Research And Adjacent Intersection Coordinate

As the skeleton of city road network, urban expressway plays a principal role in the city traffic system, which shoulders the responsibility of the large number of middle and long distance fast transportation task. However, with the continuous economic and social development of the city, the volume of traffic grows gradually, the traffic congestion problem of city expressway occurs frequently, and the advantage of original city expressway is weakened. There are many reasons leading to traffic jams of city expressway, where the off-ramp vehicles is a more prominent problem, which cannot timely ease and cause the queue back to the mainline. Therefore, it is worthy of investigation to solve this problem.In this paper, taking the elevated expressway off-ramp, ramp and the intersection between the connecting segment and the downstream cross linking port as the research object, the method is investigated to study and solve the elevated rapid off-ramp congestion from the setting and control of off-ramp. This paper firstly analyzes the congestion reason, the connecting position between the exit end and the ground road and vertical position and control method, which makes the theoretical preparation for the later research. For the off-ramp settings, through transfer matrix theory, this paper emphatically analyzes the exit ramp cohesion method to calculate the minimum length. For the control of the off-ramp, based on the green phase and phase advance activation method, the acceptable queue length control strategy is proposed by changing the line detector layout position from road intersection traffic efficiency. Taking the queue length as the constraint condition, the coordination control strategy is designed under the premise of adding the second light on ground road near the off-ramp exit end. Finally the control strategy for off-ramp is designed basing on the bus signal control. In this paper, the control strategy is verified by VISSIM software, and the results are shown as follows:the off-ramp detector layout in line at the exit ramp exit end has an advantage over off-ramp detector layout in line acceptable queue length at the off-ramp vehicles driving away off-ramp priority, and the acceptable queue length control strategy in terms of road intersection traffic efficiency has more advantages.