Sustainable tunnel lighting: One decade of proposals, advances and open points

The lighting of road tunnels and underpasses is one of the most critical tasks when dealing with illumination due to, at least, two reasons. On one hand, the slightest visual impairment, by default or excess of light, puts human lives at immediate and high risk. On the other hand, the lighting of tunnels is extremely expensive in economic, energy, environmental and even social terms. The compromise between safe tunnels and sustainable lighting installations, has needed deep attention and optimization until recent times. Although there has been interesting attempts before, it wasn't until the last decade, when groups around the world seriously started to make reliable models and proposals to decrease the impact of these installations whilst keeping road safety in tunnels. This delay compared to other areas of tunneling is due to the high complexity of visual perception, stimuli inter-pretation, and drivers reactions. In this work, an exhaustive review of what has been done and what is still to be done is presented.

Automated summary

The lighting of road tunnels and underpasses is crucial for safety and involves significant costs in terms of economy, energy, and environment. In recent years, global groups have started to make reliable models and proposals to reduce the impact of these installations while ensuring road safety.