California Partners for Advanced Transportation Technology

PATH Task Order 6329 has as its two main goals 1) to create a software tool which can be used to design and test ramp metering systems for freeways, and 2) to prepare necessary software to conduct a field test of a queue control algorithm developed under T.O. 5503. Both of these objectives are directed towards improving the effectiveness of ramp metering strategies for freeways by using advanced technologies in traffic sensors (Sensys), data storage (PeMS), and ramp metering algorithms (Alinea, SWARM).

The Ramp Metering Design Tool (RMDT) has been designed to meet the first of these goals. The RMDT is a Matlab based software tool that guides the user through a clearly defined sequence of steps leading from data collection (using PeMS), through calibration, to simulation. The final outcome of the process is a calibrated model of the freeway which can be used to test different operational strategies, such as ramp metering. The Ramp Metering Design Tool was tested by Jan Hueper, an exchange student from the Institute for Transport und Automatisierungstechnik at the Leibniz Universitaet in Hannover who had no prior experience with the software or background in traffic theory, to successfully construct a calibrated model of the I-80 East freeway, in a period of about 4 months. The step by step I-80 East model construction and calibration process is described.

Traffic controllers were evaluated and the 2070 controller was chosen to be used for the field test. The Hegenberger Rd. loop on-ramp to S/B 880, in District 4, was selected as the test site. A 2070 controller was acquired and the Universal Ramp Metering Software (URMS) source code was obtained, studied, and discussed with its developer to identify required modifications for the inclusion of ramp metering and queue control algorithms. In addition, the Sensys wireless vehicle detection system was analyzed and meetings were held with Sensys Networks Inc. personnel to determine the sensor needs for the project. Finally, a new hardware-in-the-loop on-ramp simulation tool was developed to debug and test the Universal Ramp Metering Software.