Summary: Evaluation of newly designed tunnel elements

This study carried out within the Austrian Road Safety Board, sought to evaluate some newly designed tunnel elements. Data was collected from 69 test persons driving along a 30 km test route on the Austrian highway A9. Tunnel characteristics such as portal design, lighting situation, safety features were assessed by instrumented observation of driving behaviour, thus recording speed choice and driving errors, semi-structured interviews and psychological questionnaires.

Results indicate a better perception and increased subjective feeling of safety for newly designed or re-constructed tunnels. Results are supported by several data sources.


The aim of the study was to analyse the impact of new designed tunnel characteristics such as re-designed tunnel portals, lighting situations and different safety features on real driving behaviour. The test route on the Austrian highway A9 was about 30km in total, thus including tunnels of old and new design with one or two tubes and with different speed limits.


Empirical data was collected from 69 subjects by means of psychological questionnaires, a semi-structured interview and from test drives with a vehicle, equipped with video and data sensors.


Results show that the newly designed or re-constructed tunnel characteristics was perceived positively by test subjects, especially with regard to the feeling of subjective safety. This result is supported by objective driving data, such as registered driving errors and speed choice. However, the modern portal design of new tunnels were assessed less well-arranged, The current high level of tunnel design could be observed on any evaluation level.

One of the basic principles of the successful improvement of tunnel design is due to a clean and bright appearance and corresponds to perception demands by a proper lighting design. Hence, room for potential improvement is not be found within the tunnel itself, but in the tunnel entrance area, the highway alignment as well as positioning potential interchanges.


The implementation of the mentioned instruments, especially using the sensor-aided vehicle, allows for identification and mitigation of potential high-risk sites before accidents take place. This result can be regarded as a matter of substance as dangerous situations often can not be identified in the state of planning and design, but occur in real circumstances. We suggest to implement the used method of intrumented monitoring of real (driving) behaviour directly after infrastructure realisation in order to get a safety assessment before accidents happen.