Figure $3.$ Shock Wave Phenonmena at a Signalized Intersection

$($Source: May$)$

The second simple traffic situation, shown in Figure $4,$ is at a lanedrop location on a long bridge during a morning peak period. The capacity of the lane$-$drop location is constant over time, but the demand varies. Like the typical peak period, the traffic demand increases. The demand exceeds the capacity of the bottleneck and a shock wave starts to form backwards. The shock wave continues to form backwards until the demand equals the capacity of the bottleneck. During this period the shock wave remains stationary. Finally, the rush hour demand decreases below the capacity of the bottleneck and the shock wave slowly recovers forward. In addition, a frontal stationary shock wave occurs at the bottleneck as long as the bottleneck operates at capacity.