2. Literature Review

Lu claims that the virtual drop lane congestion on the highway can be controlled by on-ramp signal metering, variable speed limit, and off-ramp metering\cite{Lu_2011} .  The goal is the maximization of repeatable bottleneck flow to approach its capacity flow. To achieve this goal, make a discharge ramp right before upstream of the congestion section. However, case 1; upstream is congested with no queue in the bottleneck, and case 2; both upstream and the part of the bottleneck stretch are congested with queue within the bottleneck, are not considered. The Figure \ref{577805} -a) shows if the discharge flow is less than \(2q_b\) there is no congestion. However, fgure \ref{577805} - b)