Modeling and optimal control of travel times and traffic emission on freeways

Abstract In this paper a modeling method and a control approach is proposed for minimising both travel times and traffic emission on freeways. A simulation-based investigation among emission models is performed to determine the model to be engaged for a model-based control. The chosen model is imposed on a second-order macroscopic traffic model. A constrained LQ control is proposed for optimization. An emission-optimal control and a multicriteria (travel time and emission) optimization are compared to conventional, solely travel-time optimal control. Simulations prove that ramp metering can be used to reduce both emission and travel times on motorways.