Summary

Microscopic simulators, such as Paramics, have shown the potential to provide a good alterative to real-world testing of ramp-metering strategies. This project is intended to develop an integrated ramp-metering design and evaluation platform for conducting ramp metering studies using Paramics. The platform will have intuitive graphical interfaces in order to facilitate Caltrans practitioners.

With the use of the proposed platform, both Caltrans practitioners and researchers will benefit in the following aspects:

1. Training of Caltrans personnel in the proper operational aspects of ramp-metering systems, including: initializing parameters, fine tuning of parameters, performance analyses, and hypothetical "what if" simulated testing;
2. Designing or implementing a metering strategy to a target network;
3. Analyzing, evaluating, and improving metering operations;
4. Testing new metering algorithms and fine-tuning parameters.

Methodology

The integrated ramp metering design and evaluation platform will be developed based on our extensive experience with PARAMICS micro-simulation, ramp metering and computer programming. The platform has two functional components, design and evaluation, that can be used to design and evaluate a library of metering algorithms currently in use in California, including District 3, 6, 8, and 11's SDRMS, and District 7 and 12's SATMS, as well as a series of adaptive metering strategies (e.g., ALINEA, and SWARM) that could potentially be applied. These metering algorithms will be developed as Paramcis plug-ins based on the hierarchical approach established at UCI ATMS Testbed.

The ramp metering design tool of the platform handles how to implement a metering algorithm within a target freeway corridor based on traffic flow analysis, requirements of the metering algorithm, and geometric data of the target freeway corridor. In general, traffic flow analysis based on historical traffic data is required for the metering design. Loop detector data are the major data source used to support metering design. Based on loop data, we can perform capacity analysis, shockwave analysis, and flow-occupancy analysis, etc. We will investigate how to use loop data for the design of various algorithms based on their exclusive features. Also, since ramp metering in general, and advanced metering algorithms in particular, rely on the quality of the loop detector data, we will conduct research on how the inaccuracy or uncertainty of detector data affects the performance of metering control

The ramp metering evaluation tool generates performance measures, each of which corresponds to an aspect of ramp metering study, from simulation runs. These measures can be used for analyzing, evaluating and fine-tuning the design of the ramp-metering algorithm in the target network.