By means of a life-cycle cost analysis (LCC), an economic evaluation of protective devices was carried out. As a functional unit, a 1.0 km long section of a protective device of containment level H2 was defined from standard elements in the medial strip of a freeway. The observation period of 25 years includes the following lifecycle phases: • Investment: tendering, planning and commissioning as well as manufacturing and construction; • use phase over the lifetime; • costs at the end of life: demolition, dismantling and disposal. With the help of a literature search, a data collection together with stakeholder and various expert discussions, the relevant cost types as well as their value for the selected exemplary systems were determined. To make the cost data comparable, the reference year 2018 was defined. The economic evaluation of the protection facilities was based on the net present value of the resulting life cycle costs. The results show that investment accounts for the largest share of lifecycle costs, while usage costs play a minor role. The latter are only relevant for open tracks (> 5 %) and are dominated by green maintenance costs. The sensitivity analyses proofed that the results are robust. The end-of-life costs and their sensitivity vary between the protective devices and should therefore always be considered on a case-specific basis. The following rule can be used to roughly estimate the materiality of the usage costs: If the annual usage costs are > 0.27 % of the construction costs, they are significant (> 5 %). To estimate a case-specific LCC, the boundary conditions can be freely entered in the Excel calculator provided. The study identified further research needs, mainly regarding individual yet insufficiently quantified cost types beside others for the installation of the protection device in the hard shoulder. Also, the internalization of external environmental costs such as costs for CO2e emissions is recommended. (Author/publisher)
Abstract