Key statistics show that tunnels are overall less prone to accidents than corresponding open-air sections. The reason for this is that tunnel traffic is not exposed to weather, intersections, mutual glare and pedestrian conflict.
Entry and exit areas, if not properly lit, can become dangerous traps for road users.
In fact, the glare and black hole effect can make the driver completely unable to see a column of trailing vehicles or other obstacles, preventing them from reacting in time.
Luminance, illuminance and uniformity levels are set by regulations depending on traffic characteristics, road condition and travel speed.
The representation below shows the arrangement of the luminaires according to the different luminance levels required in the tunnel areas.
Reinforcement lighting should be controlled throughout the day to make entry and exit from the tunnel as safe as possible.
At night, the reinforcement system is turned off and the permanent system dimmed according to the tunnel characteristics.
The best control is achievable by adjusting the portals with luminance probes for instantaneous power adjustment according to the external light level.
