This plugin implements the SATMS (Semi Actuated Traffic Metering System) ramp metering algorithm in PARAMICS. The SATMS is one of the ramp metering systems used in California. It is currently deployed in District 7 (Los Angeles) and District 12 (Orange County).

The SATMS can be operated under traffic-responsive metering control or pre-timed metering control. The theory behind the traffic-responsive metering control of the SATMS is based on demand-capacity control.

The SATMS provides two sets of metering parameters, which are referred to as “plan A” and “plan B”. The plan in use at any given time is selectable via time-of-day (TOD) table entries (see picture below) or via communications. It two TOD tables and each TOD table has 48 TOD entries, and 16 holiday tables provided to control by time-of-day and day-of-week. For each controller, it can control up to 3 meters.