LCCA for silent surfaces

Traffic noise (and in more detail rolling noise) affects the health of thousands of citizens. Consequently a number of silent technologies (quiet surfaces) are available, with different weaknesses, noise performance, and expected life. This notwithstanding, addressing noise impacts from a Life cycle cost analysis (LCCA) perspective is still an issue. Indeed, characterization factors, inventory data, underlying methodology are neither clear nor well established. Complexity increases when not only environmental costs but also agency and/or user costs are considered as a whole. This implies that the assessment of the “overall” appropriateness of a “silent technology” may emerge as uncertain. In the light of the above, the study described in this paper focuses on setting up a methodology for the synergistic consideration of agency, user and environmental/noise-related costs. The methodology set up was applied to a given case study. Results can benefit both researchers and practitioners. are different methods to derive these values (ACPA, 2011; West et al, 2012). Furthermore, from an epistemic and mathematic standpoint, several issues emerge (Weeds, 2001; Praticò and Casciano, 2015); ii) The discount rate (interest and inflation rates) can be assesses, in the U.S., through the OMB circular A-94, Appendix C. Anyhow, it is extremely variable and results may depend on the selected options; iii) the estimate of user costs (UC, delay costs, crash costs, vehicle operating costs) is debated, uncertain, and difficult (even if software is available, see Caltrans, 2011). Furthermore, there are doubts about merging agency and user costs in LCCA analyses (current FHWA policy does not recommend this practice) and UC value is usually higher or comparable with respect to agency costs (AC, see Delwar and Papagiannakis, 2001); iii) functional, structural, premium properties of pavements have to be considered in terms of agency costs, including their variability of time for the given pavement type (macrotexture modeling,,,,, a study on the relationship.....; iv) the assessment of the environmental impacts is included in LCCA, but the synergistic consideration of environmental and “traditional” (i.e., UC, AC) impacts poses theoretical and practical issues (Praticò et al, 2010; Praticò et al., 2012). This consideration pertains also to the simultaneous assessment of different environmental impacts (e.g., noise and carbon footprint of a pavement); v) several authors and road agencies (Mallela and Sadasivam, 2011) observe that the monetized impacts of user costs include travel delay costs, vehicle operating costs, crash costs, emissions costs, impacts of nearby projects. At the same time, they classify under other, non-monetary impacts the following items: noise, business impacts, inconvenience to local community. This method implies that environmental impacts are split into two different classes: monetized and non-monetary. Although necessary from a practical standpoint, from a logical standpoint, this division is quite unsatisfactory because: i) the same emission costs were once non-monetary and are now monetized through a given methodology; ii) this brings to variable results, based on CO2e unitary cost. For noise-related impacts, Cucurachi and Heijungs, 2014 provided characterization factors to allow for the quantification of noise impacts on human health in the LCA framework. Garrain et al, 2009 proposed a specific indicator as the best unit to measure the negative impacts of noise upon human health. Doka, G. (2009) provided practical figures to estimate road, rail and airplane noise damages for Life Cycle. Buckland and Muirhead, 2014 analyzed the expected reduction in property value for an increase of 1dB(A). They found reductions in the range 0.22.2%. In terms of monetary evaluation of road traffic noise, values which range from zero (when the 24-hour A-weighted equivalent outdoor sound level is about 50 dB) to about 1040 €/year/exposed person (for 72dB) were proposed (see Vanchieri, 2014). Overall, despite the simplicity of the logical bases for the derivation of noise costs (the higher the distance from a given threshold, around 50-55dB, the higher the cost), the following specific criticalities may be highlighted: i) order of magnitude of the unitary costs (per dB, per person, per year); ii) linear versus non-linear dependency on dB; iii) variability over time of pavement noise performance (Licitra, 2014).