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Open Access Publications from the University of California

Tools for Operations Planning (TOPL2)


TOPL is a suite of tools to specify operational improvements including ramp metering, incident and demand management, auxiliary lanes, traveler information, and to quickly estimate the benefits that such improvements can realize. TOPL is based on the macroscopic cell transmission model (CTM). Advances under TOPL2 can be classified under (1) theory, (2) software and algorithms, and (3) applications.

In terms of theory, the CTM model for a freeway was thoroughly analyzed and extended to arterials. In software, the major advance was the development of Aurora—an object-oriented simulation framework. The major application of the theory was to congestion pricing and control. Aurora was used to simulate I-880. The versatility of Aurora was exhibited by its use to simulate an arterial, signal control, and to model sensors. Significant theoretical and empirical progress was made in the statistical imputation of ramp data in the absence of actual measurements.

The website of the TOPL project is

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