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Aalto Lighting Unit
AEF Programme

Light Energy – Efficient and Safe Traffic Environments



Lighting is a large and rapidly growing source of energy demand; it consumes 19% of the global electricity production. For road traffic, lighting is one of the most efficient road safety measures evidenced by cost-benefit calculations (mean effect on fatal accidents -60%). In search for the most optimised and energy-efficient traffic infrastructure, life cycle costs, service and business models and societal impacts of the new technologies need to be analysed and optimised for the current socio-techno-economical system.

LEDs will become the light source with highest energy-efficiency (lm/W) in the near future. It is foreseen that by 2030, LEDs will cover 90% of the outdoor light sources resulting in 50% decrease from baseline energy consumption. The future use of mesopic photometry has huge impacts on outdoor lighting energy-efficiency, as light is provided at wavelengths most efficient for human vision. There is a perfect match between the adoption of mesopic photometry and LED development, as the spectral output of LEDs can be easily tuned at any light level.

In smart (adaptive) lighting control light is provided only when and where needed, based on constant measurement of traffic data and road conditions. Road lighting and traffic safety are tightly inter-connected. Currently, there is a serious lack of knowledge on how the traffic safety is affected by adapting lighting for varying traffic and road conditions. As the actual safety effect can be evaluated only after long time periods, indirect measures are needed.

Life cycle assessments (LCA) are needed for systematic analysis of the environmental impacts of lighting products and services. Several challenges remain in conducting LCAs of LEDs and the actual environmental impacts of LED technology are still unknown. Mobile mapping systems provide novel ways to collect street and traffic environment data for design, maintenance and environmental purposes. The societal impact calls for user-centric approach, utilising Living Labs, simulators and service design methodologies to produce information for optimizing the use of energy in terms of user experience and needs of various user groups and stakeholders.