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Butt A.A.,KTH Royal Institute of Technology | Toller S.,Swedish Transport Administration Trafikverket | Birgisson B.,KTH Royal Institute of Technology
Journal of Cleaner Production | Year: 2015

Life cycle assessment (LCA) methodology can be used to assess the environmental impacts of a road system over its entire life time. However, it is very important to align the potentials and limitations of such tools with their intended purpose. For the LCA to be useful for the decision support in a procurement situation, it should therefore be important to have a clear understanding of the technical features (attributes) that build up the life cycle phases. In this paper, different types of decisions situations are outlined based on at what level of complexity (network or specific project) and at what stage within the planning process (early planning or late planning/design) the decision is to be made, and relevant methodological choices for these decision situations are discussed. Further, the attributes that are important to consider in an asphalt road LCA that seeks to serve as a decision support in a procurement situation are suggested and technical features for these attributes are outlined with focus on Energy and GreenHouse Gas emissions. It can be concluded that in order to aid the implementation of green procurement, it would help if the attributes of the system are defined in a transparent manner and consistently calculated. It is, however, also important that the attributes should mirror the material properties used in a pavement design and therefore be closely linked to the performance of the road in its life time. It is also recommended to report the feedstock energy in the road LCAs. © 2014 Elsevier Ltd.

Li M.,Swedish Transport Administration Trafikverket | Persson I.,AB DEsolver | Spannar J.,Swedish Transport Administration Trafikverket | Berg M.,KTH Royal Institute of Technology
Vehicle System Dynamics | Year: 2012

This paper studies the use of second-order derivatives of track irregularities (longitudinal level, LL) for assessing vertical track geometry quality. Both a single-degree-of-freedom and a three-DOF vehicle-track model are investigated in order to explain theoretically why from the aspect of vehicle-track dynamic interaction it is relevant to consider not only the amplitudes of LL but also their second-order derivatives (LL2). Simulation results are then presented to demonstrate that dynamic vertical track forces are more correlated with the second-order derivatives (LL2) than to the amplitudes (LL) themselves. A comparison of the power spectral density (PSD) spectra for typical track reveals that it is more convenient to use the PSD spectra for the second-order derivatives than for the amplitudes, as the curves for the second-order derivatives are flat within the short wavelength range. Finally, the practical use of derivatives within the maintenance management system in order to achieve improved assessment of track geometry quality is also discussed. © 2012 Copyright Taylor and Francis Group, LLC.

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