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Ecological balance

In a life cycle assessment (Life Cycle Assessment, LCA), the individual processes of a product system are analyzed in detail regarding their environmental impacts. All relevant resource consumption and emissions throughout the entire life cycle – including all pre-stages – are systematically recorded and accounted for. The procedure for life cycle assessment is defined in the ISO 14040 standard (2014).

Life Cycle Assessments in the Context of Swiss Road Surfaces

In the area of Swiss road surfaces, particularly SDA surfaces, several studies already exist:

  • PLANET EP2 (Liechti et al., 2016)1 analyzed various types of asphalt using detailed process models and specific pollutant measurements across numerous impact categories.

  • Kytzia and Pohl (2021)2 examined the influence of processing temperature and the proportion of recycled material – assessed in UBP.

  • Lenk (2023)3 compared mastic asphalt with SDA-8 rolled asphalt in road construction.

  • Piao, Bueno et al. (2022)4 analyzed the environmental impacts of recycled rubber from used tires in SDA surfaces – considering the effects on other material flows.

These studies covered the entire life cycle of conventional surfaces, but without the usage phase of the road. The focus was on construction, maintenance, and deconstruction.

Extended Consideration Including Noise and Usage Effects

For the first time, the work of Piao, Heutschi et al. (2022b)5 considered the usage phase – with particular attention to noise impact. Here, SDA surfaces were compared with SMA surfaces, and the noise impact was assessed based on DALY (Disability Adjusted Life Years) – that is, lost years of life due to death or health limitations.

The results show:

  • SDA surfaces cause 70% more greenhouse gas emissions in construction, maintenance, and deconstruction,

  • but significantly reduce noise pollution – leading to 40% fewer DALY.

A clear conflict of objectives between climate protection and health protection.

BAFU Study on Environmental and Usage Effects 6

Low-noise road surfaces – Life cycle assessment and life cycle costs

A more comprehensive consideration was carried out by Schindler et al. (2024) on behalf of BAFU. In this study, SDA 4 and SDA 8 surfaces were compared with ACMR 8 and AC 8 surfaces. The focus was on the usage phase, which considered not only noise but also microplastic wear and fuel consumption (based on rolling resistance).

Results:

  • SDA 4 surfaces exhibited up to 20% lower rolling resistance due to their fine surface texture (Schlatter, Bühlmann, and Schindler, 2021)7.

  • This significantly reduced usage emissions.

  • In the overall assessment based on UBP, the SDA 4 surface caused the least environmental impact.

  • In comparison to the reference surface ACMR 8, it was found:

    • SDA 4: -4% environmental impact

    • SDA 8: -1%

    • AC 8 H LA: nearly identical (-0.1%)

The decisive factor for the good performance of the SDA 4 surface was primarily its noise-reducing effect, which compensated for the higher ecological impacts of construction and deconstruction.

For validation, various sensitivity analyses were conducted. The core statements remained stable under assumptions such as:

  • longer lifespan of conventional surfaces,

  • acoustic maintenance on low-noise surface types,

  • higher recycled content in the mix,

  • increasing share of electric vehicles.

A particularly promising lever is the optimization of the rolling resistance – here there is an even greater ecological and economic potential.

Learn more about the life cycle assessment of LAB at 30 km/h

On behalf of the city of Zurich, the study Life Cycle Assessment and Life Cycle Costs of Low-Noise Surfaces at 30 km/h
Supplementary report to the study “LCA LAB” (BAFU 2024) was prepared. 8

Life Cycle Assessment and Life Cycle Costs of Low-Noise Surfaces at 30 km/h

The SDA 4 surface showed the lowest environmental impacts and total costs compared to other surfaces studied at speeds of 50 km/h (T50) and 30 km/h (T30). Over the entire life cycle, SDA 4 reduces environmental impact compared to the reference surface AC MR 8 by nearly 3% (around 4% at T50).

Although noise emissions at T30 are overall lower, the ecological advantage of SDA 4 remains relevant. At T30, the fuel savings from the low-noise surface also gain importance, as energy consumption is relatively higher here.

Overall, the analysis shows that low-noise surfaces – particularly SDA 4 – are advantageous both ecologically and economically at 30 km/h and contribute to a measurable reduction in environmental impact.


1 Liechti, J. et al. (2016) Research package PLANET EP2: Life cycle assessment of low-temperature asphalts. Swiss Association of Road and Traffic Professionals (VSS).
2 Kytzia, S. and Pohl, T. (2021) ‘Life cycle assessment of asphalt production’, Road and Highway, pp. 641–652.
3 Lenk, J. (2023) Life cycle assessment (LCA) of mastic asphalt as a surface layer on Swiss national roads. BFH.
4 Piao, Z., Mikhailenko, P., et al. (2022) ‘Analysis of Environmental Burden Shift for Using Recycled Concrete Aggregates in Low-Noise Asphalt Pavement’, in Transportation Research Board 101st Annual Meeting. Transportation Research Board 101st Annual Meeting, Washington, DC
5 Piao, Z., Heutschi, K., et al. (2022b) ‘Environmental trade-offs for using low-noise pavements: Life cycle assessment with noise considerations’, Science of The Total Environment, 842, p. 156846. Available at: https://doi.org/10.1016/j.scitotenv.2022.156846
6 Schindler, J. et al. (2024) Low-noise road surfaces – Life cycle assessment and life cycle costs. Bern: ArGe LCA-Road; Federal Office for the Environment BAFU.
7 Schlatter, F., Bühlmann, E. and Schindler, J. (2021) Rolling resistance on low-noise surfaces in Switzerland. Grolimund + Partner AG.
8 Singer, T. et al. (2025) Life Cycle Assessment and Life Cycle Costs of Low-Noise Surfaces at 30 km/h Supplementary report to the study “LCA LAB” (BAFU 2024), ArGe LCA-Road, City of Zurich.
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