In a time when the concept of sustainability is gaining increasing attention among the public, as well as among stake holders and policy makers, informing people about what the most sustainable choice to make is, is crucial in leading people in the right direction.  Travelling is an activity requiring a traveller to make multiple choices, with one of the choices being which route between two places to take. The transport sector is also a strong contributing cause to global issues such as climate change, wherefore choices made in relation to transportation are highly relevant in regard to sustainable development.  Up until today, most traffic information systems for passenger car users, only provide travellers with suggestions about the fastest, or the shortest, route option. This study aims at proposing a modelling structure using GIS software, that could also return the most sustainable route alternative.  The complexity of the many spatial impacts of road transportation is thoroughly discussed in the literature review, together with dilemmas regarding route choice behaviours. A proposed modelling structure is presented, with the structure also empirically being examined as a “proof of concept”. The empirical work takes place in the urban area of Hörnefors, Sweden, and findings confirm the applicability of the proposed workflow.  In the specific case of Hörnefors, three distinct route options are investigated, in relation to four sustainability impact variables. The variables investigated are fuel consumption, air pollution, noise, and safety. Results show that the, by far, longest route, is in fact returned as the most sustainable route option. The other two route options exhibit impacts of around double the amount of impacts yielded by the most sustainable one. The generalised sustainability cost is significantly mostly determined by the air pollution variable, due to its far-reaching spatial dispersion patterns yielding impacts even at long distances from a road.  The potential application of the inclusion of sustainability in traffic information systems are additionally reviewed, according to the behavioural mechanisms mentioned in the literature 4review. Estimations of in what contexts “most sustainable route” suggestions are potentially most likely to yield behavioural changes, are also made, and assessed. Conclusions suggest that an inclusion of “most sustainable route option” modelling into travel information systems, have the highest potential to affect route choices when the user is driving at locations previously unvisited, due to the inexistence of a status quo route in such contexts.