Several thousand communes in France switch off their street lighting in the dead of night. For the communes listed on the NuitFrance website, the majority turn off their street lighting between 11pm/midnight and 5am/6am.
In some cases, lighting is not turned back on in the morning, or is even completely switched off in summer. Lighting can be switched off totally or partially, over all or part of the municipal territory, all year round or not.
The “Nuits sans lumière” (Nights without lights) initiative has been running on Reunion Island for several years now, during a sensitive period for wildlife. For almost 2 months, a number of communes have switched off their street lighting throughout their territory, or in certain sectors, to protect Barrau's petrels and Bourbon's black petrels from light pollution.
Two studies carried out on bats (Glob change Biolog 2015, Anim Conserv 2015) show that the effectiveness of the measure depends above all on the time slot during which the lights are switched off. The results would probably be similar for other species whose activity is actually more crepuscular than strictly nocturnal (e.g. terrestrial mammals, nocturnal birds of prey).
In fact, as explained above, many animal species show a peak of activity just after dusk, then another before dawn.
Extinction must therefore be carried out as early as possible, so as not to occur after the emergence of these species.
Extinction in the middle of the night is probably very beneficial for certain groups that are active in the middle of the night, for the flora or for all species that navigate with the starry sky (migrating birds, for example). It immediately restores visibility of the night sky, which is also in line with the issues at stake for humans (astronomy, nocturnal heritage, night-time tourism). Last but not least, this measure offers immediate energy savings.
One obstacle to switching off public lighting at the heart of the night may be the fear of liability on the part of elected representatives in the event of an accident (road accident, theft, etc.).
The mayor is in fact the only authority competent to switch street lighting on and off. However, the law does not require him/her to illuminate. However, the mayor is under an obligation not to endanger the lives of others (Penal Code, article 121-3), including through negligence (Civil Code, art. 1383).
He may therefore be held liable in the event of a road accident caused by faulty lighting.
However, there is no case law holding mayors liable for road accidents that occur when street lighting is deliberately switched off.
There is a feeling of insecurity linked to people's ancestral relationship with darkness (fear of the dark).
However, a systematic review shows that street lighting does not reduce the fear of crime.
Also, a scientific study shows that different lighting scenarios (switching off, dimming, full lighting) do not vary the crime rate.
