Decrease of the maximum speed in highway tunnels as a measure to foster energy savings and sustainability

The high energy consumption of the lighting installations in highway tunnels has become a hot topic in the last few years due to the high figures in terms of money, consumed energy, use of raw materials, emissions of greenhouse gases due to the remarkable number of manufactured elements, and maintenance, among others. In spite of the different strategies proposed up to date and their savings, the potential benefits of decreasing the maximum speed allowed in tunnels have not been considered in depth as a complementary measure yet. In this work, the impact of such a decrease in terms of energy consumption, number projectors, carbon dioxide (CO2) emissions, and yearly costs in energy is analyzed and discussed. The results strongly suggest the convenience of introducing maximum speed reduction in traffic regulations which, in addition, could create positive synergies with traffic safety.