Cooperative ramp metering simulation

The increase of vehicle numbers in recent decades resulted in road traffic congestion problems. Such congestions are a characteristic of densely populated urban areas and occur daily during morning and afternoon rush hours. Urban areas have been suffering from the lack of space needed to build new road infrastructure. The traffic congestion problem can be solved by applying new traffic control approaches from the domain of intelligent transportation systems (ITS). One of the applied methods from ITS is known as ramp metering and is used to increase the throughput of urban highways with many on- and off-ramps. Nowadays ramp metering is used in cooperation with additional control approaches like variable speed limit control (VSLC). Prior to implementation, such cooperative traffic control systems have to be tested in simulations using real world traffic data. One of the used simulators is CTMSIM which enables macroscopic simulation of highway traffic and local ramp metering approaches. In this paper the CTMSIM simulator is augmented to enable simulation of cooperative ramp metering algorithms, stand-alone VSLC, and cooperation between ramp metering and VSLC. Augmented simulator is tested using some limited available traffic data with the Zagreb bypass urban highway as a case study.