California Partners for Advanced Transportation Technology

The control of a traffic corridor, which consists of two major component - freeway system control and arterial street system control, aims to improve flows on both freeway and arterial streets, and has been demonstrated as an effective means to increase the level of service of a corridor system during peak periods.  Ramp metering, or ramp control, has been considered to be a very important component of corridor traffic control.  Ramp metering is the application of control devices such as metering signals to limit the number of vehicles entering a freeway.  The fundamental philosophy of ramp metering is that the corridor can maintain its optimal operation by regulating the freeway demand to be under its capacity.  Maintaining the optimal operation of the corridor would provide congestion avoidance and accordingly travel time savings.