New luminous asphalts may remplace street lamps
On both sides of the Channel, companies and local governments are experimenting new types of roads made of phosphorescent asphalt. Those roads absorb sunlight at daytime and restitute it at nighttime allowing to reduce or even completely remove street lighting, saving therefore much elecrticity without depreciating night vision and safety.
In all developped countries, where motor vehicles are now a common means of transportation, street lighting has become an essential application for safety and prefention of traffic accidents, and it also plays a role in decreasing urban delinquency. It requires however an important electricity consumption, thus a significant part of local governments’ spendings for energy supply. Moreover many voices denounce a waste of energy for street lighting, and every year numerous studies and publications demonstrate we can make important savings. In the pursuit of this goal, luminous roads are new technologies currently making their first steps.
In Limoges, France, the “Lumiroad” system has been built in january : it is a 2-way road made in a special bitumen whose mixture includes pale sand and reflective pigments. LED lamps whose intensity varies according to current needs are placed above this self lighting road. Electricity consumption is thus reduced by 60% for the affected road portion, and the cost of installing such an asphalt is compensated in only 3 years. In England, a company has developped a phosphorescent spray which can be applied on any surface (concrete, asphalt, wood or gravel) and made water-proof and skid-proof by a transparent protective coating. This product has been tested in a Cambridge garden, it can be used in various places and its creators affirm it can make possible total suppression of street lamps in some situations.
A general use of these methods is not forecasted because although the idea is entirely linked to sustenable developpment, their effects on environment at every single stage of the products’ conception have not been meticulously studied and are not fully known.
These applications should nethertheless been enhanced because they may in a near future be added to the list of actions undertaken against overlighting : revision of lighting plans (in order to reduce the number of lamps), redirection of lamps towards the ground (because any light directed towards the sky is wasted) and remplacement of mercury vapor lamps by sodium vapor or LED ones, amongst other solutions. Luminous asphalts will maybe take part in the fight against light pollution in large urban areas, which becomes an important matter because of its harmful effects on physical and psychological health of humans and animals.