The need for road lighting
It is an incontrovertible fact that road lighting is now an integral part of our civil infrastructure. It assists in the safe movement of road traffic and has brought light into our towns and cities, enhancing our lives and helping remove crime from the streets. There is an ongoing price to pay, and a balance between cost and benefit to the community must be understood.
Will there be a need for road lighting in the future? As yet unproven advanced technologies for motor vehicles such as intelligent lighting and speed and distance control may remove the need for traffic route lighting. In urban areas there is increasing encouragement to walk and cycle in the interests of health, and in an effort to reduce pollution and congestion. However, for the foreseeable future the need for road lighting will remain.
The future of road lighting
Road lighting will be under increasing legislative and moral pressure to reconcile its responsibility to sustainability and climate change. The reduction of sky glow, light trespass, light wastage and the adverse effects of artificial light on wildlife are all under scrutiny. The needs of an aging population should be taken into account. As the human eye ages it becomes more susceptible to glare and the ability to distinguish details reduces. Light sources with good colour rendering will help ameliorate this situation.
The rapid development of LED technology indicates that the LED could be a key light source in the near future. Luminaires are being developed without the design constraints imposed by traditional lamps and optical systems. Modern optical control materials and techniques are meeting the challenge of controlling the light from LEDs. LED drivers can be linked to control systems enabling dimming, colour changing and adaptive light distributions. Service lives of up to 100,000 hours have been predicted, with little or no maintenance, provided that the luminaire design incorporates good thermal management of the LEDs and their electronic drivers.
Metal halide lamps also have the potential for significant improvements in efficacy, lumen maintenance and service life. Developments in arc tube technology coupled with exclusive operation on high frequency ballasts, plus the benefits of linking to control systems for switching and dimming, show serious promise.
Adaptive lighting systems and controls
According to current lighting standards the lighting class for a particular road is chosen for the most onerous conditions. By recognising that some parameters can vary alternative classes can be justified. For example, traffic flow rates vary at different times of the night and maybe lower at weekends. The use of modern lighting control systems enables the lighting to be adapted to suit the needs at the particular time.