Using carbon dioxide emissions as a criterion to award road construction projects: a pilot case in Flanders

In the last decade, innovative technologies with regard to improved energy and material efficiency of asphalt pavement construction have been implemented by road industries. Two technologies are currently advocated: warm mix asphalt technologies and the increased use of reclaimed asphalt pavement. Unfortunately, these technologies were evaluated only by their technical and economic benefits and in most cases without an environmental impact study for the overall process. For encouraging the endeavour of the industry to implement newer greener technologies with focus to environmental benefit, the procuring authorities made an effort to enforce a sustainable approach for road works by the Project Carbon Free-ways. This pilot project included basic environmental parameters in the award criteria for public tenders on road works in Flanders. For this project two calculation tools, called Carbon Counter and Traffic Tool, were developed by the Flemish Agency for Roads and Traffic in order to estimate the carbon dioxide emissions of respectively the construction process and the traffic disturbance caused by the construction. The subject of this first public tender - with an evaluation of both tools - was the reconstruction of an asphalt road pavement in Kontich (Belgium). In this contribution the preliminary study on the methods of the tools and the main conclusions of the project are reported and discussed. The study illustrated that the current tendering process and the tools used, do have some limitations and drawbacks: the tools do not cover the total environmental impact as e.g. LCA do, the data concerning recycling or specific plant-related processes are outdated or missing and the data collection for back calculation of the total emission required too much manual efforts and shortcomings. Nevertheless, this pilot project proved to be a valued attempt to achieve more innovative and sustainable public procurement - as a first step, giving an unambiguous signal to the industry that this type of selection will be part of future tenders. (C) 2015 Elsevier Ltd. All rights reserved.