Benefit-to-Cost Analysis Framework for Intersection Illumination: A Case Study of Rural Conventional Intersections in Georgia

Lighting provides one of the most effective night-time intersection safety countermeasures. However, lighting is also one of the main contributors to intersection maintenance and operation costs. For a public transportation agency with jurisdiction over many intersections, the system-wide lighting costs can significantly deplete already limited funds for other important maintenance projects. A sound framework for conducting benefit-to-cost trade-off analysis would be beneficial to transportation agencies. Unfortunately, published works on the benefit-to-cost analysis are few and mostly dated. This paper outlines a detailed framework for conducting benefit-to-cost analysis for rural intersection lighting. The framework uses intersection lighting simulation models to generate annualized operating and maintenance cost data for different lighting levels. The intersection lighting models were developed with DIALux^® professional lighting software. This study used the framework to conduct a case study of rural conventional three-leg and four-leg intersections with at least an annual average daily traffic (AADT) of 500 from Georgia. Based on the available Georgia case study data, this paper finds that for rural intersection locations that require no electrification, basically any illumination level, including those less than the recommended minimum of 8 lux, is likely to be cost-effective for any entering AADT. However, locations that require electrification need to be evaluated based on the overall costs, entering AADT, existing crash rate, and a target benefit-to-cost ratio that signifies the level of cost-effectiveness required by the state Department of Transport (DOT). Consequently, a companion spreadsheet benefit-to-cost model has been developed to facilitate the cost-effectiveness analysis at any rural uncontrolled or stop-controlled intersection.