Coordinated ramp metering on expressway with congestion

In order to solve the traffic congestion control problem on expressway, the influencing areas in the upstream of the congestion section and a kind of heuristic coordinated ramp metering methods are focused on. According to the mechanism that traffic flow moves to the upstream of the section in the congestion duration time, queue length is considered as the significant factor in the determination of congestion influencing areas. The formula is deduced to calculate the number of ramps in the influencing areas. Due to the low adjusting speed in the single point level and wide vibration amplitude in the coordination level in the traditional methods, the density is selected as the control parameter instead of the traffic flow volume in the Bottleneck algorithm. Meanwhile, the improved on ramp coordination metering method and the adjustment rate formula are formed based on Bottleneck algorithm eliminating the limitations of traditional methods. Taken the road section from Gongyi to Luoyang on the Lianhuo expressway as the instance, coordinated ramp metering simulation analysis is conducted by using the MATLAB software. The rationality and effectiveness of the formula of calculating the number of ramps in the congestion influencing areas and the improved algorithm are demonstrated by means of the numerical simulation.