Predictive modelling of lighting quality parameters and energy efficiency of light emitting diode-based general road illumination systems with special emphasis on luminaire tilt and bracket length

Energy-efficient road illumination systems are an indispensable part of any modern society to ensure safe nocturnal transportation of freight and passengers, assure better navigation, promote improved visibility of surroundings, and diminish the probability of occurrence of accidents and crimes. Simulative estimation of pertinent photometric parameters and probable energy expenditure before commissioning of projects is very desirable to project managers, transportation engineers, local authorities, and other stakeholders for envisaging a complete picture of the deliverables and ensuring total conformity with applicable lighting and energy codes. This simulation-based work was conducted with luminaire luminous intensity distribution data tables of different light-emitting diode luminaires having type II luminous intensity distribution patterns in the simulation environment of an industry-standard lighting simulation software. Thereafter, the multiple regression analysis technique was utilized upon the simulatively obtained substantial dataset to propound a model of twenty-four bivariate quadratic polynomial equations for estimating the changes in road surface illuminance parameters, and three general equations were derived with the same dataset, two for estimating road surface illuminance parameters and one for estimating energy efficiency. The propounded model and general equations can be readily followed by various stakeholders to rapidly estimate pertinent photometric parameters and installation energy efficiency and the approach expatiated in this work can prove to be useful for exploring inter-variable relationships, providing objective functions in optimization tools, and proffering neoteric, heuristic perspectives to lighting design.