Author:

Keywords:

CIB_traffic

Abstract:

Nowadays, environmental impacts are becoming more and more important in urban network traffic management. However, traditional urban traffic management approaches are predominantly geared towards satisfying the traffic demand, and do not consider the environmental effects in the design phase. Calculation of the generated emissions is usually foreseen after the calculation of traffic volume data via traffic assignment models. This paper describes a new methodology which uses the environmental constraints as key input for defining network wide traffic management strategies. Both flow and environmental impacts are calculated simultaneously instead of evaluating the environmental impacts for a given specific flow pattern. The methodology that allows integrating the traffic and emission models, including the inversion process of utilizing environmental constraints as input for the network traffic management, will be elaborated. On the link level this means that the suggested methodology will adjust the (flow) capacity of a link according to the various environmental constraints that apply. The subsequent flow pattern represents the basis for the design of an environment-friendly traffic network. The key element in the process is the development of a speed-flow diagram on each link based on the relevant environmental constraints. Combining the speed-flow diagrams related to the environmental constraints and the fundamental speed-flow diagram a new (integrated) speed flow diagram will be obtained, addressing all constraints simultaneously. Therefore, the maximum flow which is assigned to a link applying the new speed-flow diagram will satisfy both traffic capacity and environmental constraints. Applying this methodology to a network, the assignment results represent the capacities that meet the environmental constraints (the environmental capacities); this result can thus be obtained in one step avoiding a long iterative procedure of trial and error, involving the adjustment of the link capacities. A wide range of possible traffic management and capacity management measures that can be applied to accommodate differences between flow capacity and environmental capacity will be indentified in the last part of the paper. Further details, including the proposed traffic models, emission models and traffic variables, are discussed in the paper.