Life cycle costs
The so-called life cycle costs (LCC) ideally encompass the entire life cycle of a structure, with the boundaries of consideration and the system needing to be clearly defined. They represent an integral evaluation tool that includes all relevant types of costs from construction to deconstruction.
Internal Costs
The internal costs include all expenses that the builder has to bear during the life cycle of a road. This includes the costs for construction, maintenance, and deconstruction. For SDA pavements, these costs tend to be higher compared to conventional dense asphalt pavements. The main reasons are the shorter lifespan of SDA pavements and the somewhat higher construction costs, particularly due to specific material requirements (e.g., PmB binders, highly polished resistant aggregates).
However, for a complete comparison of internal costs, it is necessary to also include alternative noise protection measures in the conventional scenario that would otherwise be necessary at noise-affected locations. This includes, in particular, noise barriers, soundproof windows, or speed reductions. Only by including these additional measures can a realistic assessment of the total costs be made.
Direct User Costs
In addition to internal costs, the direct costs of road users must also be considered. These include, among other things, fuel consumption, tire wear, and time expenditure. Schindler et al. show that SDA 4 pavements can lead to lower travel costs due to their reduced rolling resistance. These user-side savings are quantified in an extended life cycle cost analysis and compared to the higher investment costs.
External Costs
For a holistic life cycle consideration, external costs must also be taken into account beyond internal and direct costs. These are not directly borne by the builder or user, but by society as a whole. External costs include, in particular:
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Health costs due to air pollutants and noise,
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Climate damage due to greenhouse gas emissions,
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as well as economic follow-up costs such as rent losses in noise-affected areas.
This perspective allows for a comprehensive assessment of the overall societal cost-effectiveness of SDA pavements.
Study Results
A detailed investigation of internal and external costs was conducted by Piao, Waldner et al. (2022)1. In this study, SDA 4 pavements were compared with conventional SMA pavements. It was shown that the higher construction costs of SDA 4 pavements are more than compensated for by the significantly reduced health costs due to lower noise emissions. Thus, the overall result is an economic advantage in favor of SDA pavements.
In the work of Schindler et al. (2024)2, the life cycle costs are expanded to include further external factors, including health costs due to fine dust emissions and rent losses depending on road noise emissions. Various pavement types were analyzed, including SDA 4, SDA 8, ACMR 8, and AC 8.
The methodological basis of these analyses is the VSS standard "Cost-Benefit Analyses in Road Traffic" (VSS, 2022e), which defines the systematic evaluation of traffic-relevant infrastructure measures considering economic, ecological, and social aspects.
The integration of internal, direct, and external costs into the life cycle analysis shows that SDA pavements can be advantageous from an overall economic perspective despite higher construction and maintenance costs. Particularly at noise-affected locations, the reduced noise and health follow-up costs significantly contribute to a positive cost-benefit ratio. Thus, SDA pavements prove to be not only environmentally relevant but also economically sustainable solutions in road construction.
The study showed a cost shift: While users and society benefit from lower fuel costs and health benefits due to reduced noise exposure, higher costs arise for builders due to the more complex manufacturing and deconstruction process.
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