Two models for the forecast of road traffic emissions, independently developed in parallel, are comparatively presented and assessed: EPROG developed by BMW and enlarged by VDA for a national application (Germany) and FOREMOVE, developed for application on European Community scale. The analysis of the methodological character of the two algorithms proves that the models are fundamentally similar with regard to the basic calculation schemes used for the emissions. The same holds true as far as the significant dependencies of the emission factors, and the recognition and incorporation of the fundamental framework referring to traffic important parameters (speeds, mileage and mileage distribution etc) are concerned.
The existing divergences are mainly classified into three groups: (a) differences in the baseline emission factor dependencies (b) differences in the basic statistical data of the past used (c) differences in the underlying assumptions in the development of the future scenarios, referring both to the expected evolution of traffic important parameters, as well as to the expected evolution of the emission factors of the individual vehicle categories. These result in emissions, which, although presenting similar general tendencies, are different with regard to the calculated levels.
Based on the above, it is concluded that a general model framework is already available, at least as far as road traffic emissions are concerned, that could be used either on national and/or international scale and which is sufficiently analytical with regard to internal split. More work needs to be done both on the identification of the parameters to be taken into account in the design of the scenarios and on the assumptions underlying emission forecasts.