Italian Road Tunnels: Economic and Environmental Effects of an On-Going Project to Reduce Lighting Consumption

Abstract

Tunnel lighting represents a major cost item for road managers, and particularly in Italy owing to its specific geomorphological and orographic features. In 2018, ANAS, the Italian government-owned road company launched an ambitious program to rehabilitate the lighting systems of more than 700 tunnel tubes across Italy. The Greenlight plan aims to reduce consumption and improve the management of lighting systems while minimizing the impact of works. Outdated high-pressure sodium (HPS) luminaries will be substituted with state-of-the-art light emitting diode (LED) luminaries without modifying the position and the number of the existing luminaires. The project involves an amount of 155 million euros and provides a total return over a less than seven-year period. The first phase of the project involves 147 tubes and is still on-going: 28 GWh (on average 55% of the current consumption) will be saved every year against a 30 million euro investment. More importantly, the economic benefits also have a direct impact on the environment for citizens and safety levels for road users—every year more than 17,000 t of CO2 eq. and 230 TJ from combustion of fossil fuels will be saved. The lighting quality of the artificial lighting inside the tunnel will be enhanced thanks to better uniformity and the color temperature of the luminaries. The experience presented here could be useful since other road managers may pursue a similar approach in order to balance often-conflicting environmental, economic and safety goals.

Daylighting of road tunnels through external ground-based light-pipes and complex reflective geometry

“…This measure decreases the length of the most consuming zones, the threshold and the transition, and also the coefficients of proportionality between outer (L29) and inner (L th ) luminance (Peña-García, Salata & Golasi, 2019). 3) Use of pavements with higher reflectance allowing the desired luminance with less consumed power (Cantisani, Di Mascio & Moretti, 2018a;Moretti et al, 2016Moretti et al, , 2017aMoretti et al, , 2017bMoretti et al, , 2019. 4) Use of control systems to dim and manage the flux emitted by the projectors, generally including LED technologies, according to the traffic, weather and other parameters (Yao, Cheng& Lin, 2008;Leitao et al, 2009;Wang& Zhou, 2009;Ye, 2013;Lai et al, 2014;Salata et al, 2015;Salata et al, 2016;Qin et al, 2017a;Qin et al, 2017b;Renzler et al, 2018;Bouroussis, Nikolaou & Topalis, 2019;Doulos et al, 2019;Spor, Kiyak & Solak, 2019;Zhao et al, 2019;Wang et al, 2020;Qin et al, 2021;Zhao, Feng & Yang, 2021).…”

New scenarios for transport infrastructures: transition to inclusivity, resilience and sustainability

“…The opportunities proposed by scientific and technological advancements in the fields of materials (Hu et al, 2019), design (Tang et al, 2020;Cantisani et al, 2020), construction (Oad et al, 2021) and management (Sinha, 2017;Moretti et al, 2019) of transport infrastructures, allow to explore innovative solutions and contribute to ongoing transition processes.…”

A Novel Evaluation Method of Tunnel Access Zone Luminance Based on Measured Meteorological Data

“…Therefore, the massive tunnel volume also brings huge lighting energy consumption, and statistics show that the lighting energy consumption of tunnels accounts for more than 50% of the total energy consumption of tunnel mechanical and electrical facilities, particularly in summer [11,12]. Due to the high value of TAZL, the energy consumption of tunnel lighting could reach 9 times higher in the middle of the day than that of the night [13][14][15].…”