Evaluation of new coordinated feedback-based freeway ramp metering strategy using macroscopic and microscopic simulation models

In this paper, C-MIXCROS and D-MIXCROS, 2 new feedback-based coordinated ramp metering strategies, that explicitly consider ramp queues, are proposed and then evaluated using both macroscopic (Rutgers Macroscopic Simulation Environment) and microscopic (PARAMICS) simulation models (on an 11-mile-long corridor of I-295 in South Jersey) under different demand conditions. In addition to the newly proposed coordinated ramp metering strategies, a well-known coordinated strategy (METALINE (5)) and 3 other local strategies (ALINEA (6), New Control (1), and MIXCROS (1)) are also implemented using the same network and results are compared. The proportional-derivative state feedback control logic and direct regulation of on-ramp queues are employed in the derivation of this new proposed coordinated ramp metering strategy. The results from the microscopic simulation are consistent with the macroscopic simulation, where D-MIXCROS and C-MIXCROS both perform better than all other control strategies tested for all the demand scenarios. The deteriorating effect of large on-ramp queues on the total travel time is especially observed for METALINE results; the total travel time is approximately 22% greater than those of C-MIXCROS results. MIXCROS (1) is also successful in keeping the on-ramp queues at a reasonable level for each ramp. However, because it is a local ramp metering strategy, coordinated versions of MIXCROS are observed to be more beneficial both for the ramp system and at the network level. Copyright ASCE 2006.