Case study

A02 NUK22; Tunnel Ehrentalerberg

Tunnel LED lighting

Project data


A02 NUK22; Tunel Ehrentalerberg


Klagenfurt, Austrija


Public lighting, Tunnel lighting

Year of completion



On the main ring road around Klagenfurt in Austria, as part of the A2 Nordumfahrung Klagenfurt Teilsanierung NUK22 project, we reconstructed the lighting in the tunnels: Ehrenthalerberg, Falkenberg, UTF Lendorf and Trettnig tunnel. The project investor was the company ASFINAG, while the project designer was Lechner&Partner in cooperation with BUCK GmbH. The project contractor for this project was SPIE KEM GmbH.


All four tunnels in this project were located on the main ring road around Klagenfurt. The longest of them – the Ehrenthalerbergtunnel (2×3300 metres) – was also the most complex, with three traffic lanes at the entrance, which later narrowed to two lanes. Due to the high traffic density on this section of the road, closing the tunnels completely for the reconstruction was impossible. Therefore, all works were carried out at night, between 21:00 and 05:00. In addition to the night mode of work on the reconstruction, this project also required the replacement of the LED tunnel retrofit kits while retaining the existing housings. The fixed position of the luminaires presented an additional challenge, as it limited the lighting calculation possibilities and optics selection. Also, the approach traffic lane in the direction of Vienna, which connects to the highway and includes the tunnel’s entrance, made it even more difficult to unify the lights due to the different brightness requirements. In addition, the challenge was reflected in the fact that it was necessary to achieve optimal unification of the luminaires in all 4 tunnels at different mounting heights.


Regardless of the night operation mode, the work was carried out within the given deadline. In accordance with the principle of green economy, we made a combination of LED retrofits that met all the expected requirements and overcame all the existing complications in the project. By combining the LED insert kits for tunnel reconstruction: INSERT ASF 14 ASY of 234W, INSERT ASF 3 ASY of 88W i INSERT ASF 6 SYM of 170W, we achieved exceptional lighting quality, with savings in wiring material and installation work. We greatly saved electricity consumption by installing over 1800 LED insert retrofits on this project. In the Ehrenthalerberg tunnel, we installed 918 high-efficiency LED retrofit kits, with the installation of which the total installed power was reduced from 287kW to 165kW.
In this way, we achieved electricity savings of 43% in just one tunnel.

A significant contribution to these results was provided by the INSERT ASF 14 ASY retrofit of 234W, with exceptional power and energy efficiency that allows the replacement of a sodium luminaire with a power of even 400W.

Advantages of Applying INSERT ASF Retrofits in Tunnel Lighting

INSERT ASF retrofits are part of BUCK’s smart tunnel illumination system. Their range of optical solutions, including asymmetric narrow-beam and symmetric wide-beam optics, covers all requirements for optimal brightness and lighting uniformity in the tunnel. Thanks to precisely adapted optical accessories and high-efficiency LED light sources, INSERT ASF retrofits enable the achievement of all required intensity and uniformity of lighting by significantly improving all road users’ safety.

Realized advantages on the project

On this project, we installed LED retrofit kits INSERT ASF 14 ASY, INSERT ASF 3 ASY and INSERT ASF 6 SYM, which are very easy to use and mount, thanks to their “click” mechanisms. As we can see in the example of Ehrenthalerberg tunnel illumination, the energy efficiency of these luminaires achieves significant savings in electricity, which makes them an excellent ecological solution based on the principle of circular economy. We achieved large maintenance savings on this project by switching from conventional to LED lighting. The reason for this is that LED retrofits, suitable for use in harsh and humid ambient conditions and declared to have a longevity of 100,000 hours, have been installed in each of these tunnels. Switching to white LED light sources in these tunnels also enhanced safety and vigilance among road users.

Benefits for the investor

With ASFINAG as an investor, we collaborated on numerous projects such as the reconstruction of the tunnels A10 Katschberg, A09 St Pankraz, A10 St. Andra, A22 Grünbrücken Islamische Zentrum, A12 Tunnel IMST, and many others.

As in previous projects, the investment in this project was aimed at long-term energy savings by switching from traditional to more energy-efficient LED sources. Also, during the replacement of the LED retrofits, a large financial saving was achieved due to the retention of the existing housings of the tunnel luminaires.
By investing in this project, the company ASFINAG, together with BUCK GmbH and the companies Lechner&Partner and SPIE KEM GmbH, has taken another step further in its positive contribution to the environment, creating another environmentally sustainable system in the field of tunnel lighting.

Share with colleagues and friends

Url copied

Cookies allow page content to be adapted according to the needs of users, thus providing improved functionality and an improved user experience. Cookies can also be used to analyze the use of websites, as well as for advertising purposes. By clicking on "I accept" you agree to the use of cookies. You can change your cookies settings at any time.

Subscription successful!