CLR Analytics


Development of an ALINEA based coordinated ramp metering plugin

CLR Analytics developed the San Diego Ramp Metering System (SDRMS) plugin for the TransModeler software, in collaboration with Caliper, the developer of TransModeler, and Cambridge Systematics. CLR Analytics reversed engineered the SDRMS control logic being used in the field and then implemented it in Transmodeler as a plugin. The plugin allows for all features of the SDRMS algorithm to be utilized including: Rate plans per signal, AM and PM timing plans, and TOD plans. This allows traffic engineers and modelers to simulate the same ramp metering control currently being used in the field and further test different settings.

San Diego Ramp Metering System (SDRMS) is the most widely used ramp metering system in California. It is currently deployed in Sacramento, Fresno, San Bernardino and Riverside, and San Diego areas. SDRMS can be operated under traffic-responsive or pre-timed metering control. Time-of-day (TOD) table needs to be set in order to associate a time period with the control code. SDRMS has two traffic responsive control logics, which are occupancy logic and volume logic. If both occupancy and volume logics are enabled, the most restrictive of the two rate codes is applied. SDRMS provides two sets of traffic responsive and cycle rate control tables, and each of them has fifteen entries. They are referred as “A” and “P” controls (or tables) here. The table applied at any given time is selectable via time-of-day table (TOD) entries.

The developed plugin provides users with a user-friendly UI to set up various parameters of the metering control. The plugin will be used by the modelers in Cambridge Systematics to test how the improved algorithm can help decrease the traffic congestion for the I-15 corridor.
This study is a collaboration project with Cambridge Systematics, Caltrans District 11 and SANDAG.

Prime Contractor: Cambridge Systematics
Client: USDOT
Sponsor: California Department of Transportation
Time Period: Oct 2011-Nov 2011