Adequate and appropriate illumination across the highway isessential for safety. High-pressure sodium luminaires (HPS) are usually standard throughout Pakistan. However, with the advancements in illumination technologies and growing trend of energy efficiency, retrofitting of conventional HPS luminaires with light-emitting diode luminaires (LEDs) is becoming popular. Low energy consumption, high color rendering index (CRI), longer life span, and variety in correlated color temperature (CCT) make LED luminaires ideal for replacing inefficient HPS lights. The retrofitting of HPS with LED illumination system comes with a capital cost, and its feasibility depends on the energy conservation potential. This study presents a case of 4,014 HPS luminaires installed across an 85 km long highway in second highly populated city of Pakistan. A targeted energy audit of HPS illumination system was conducted and compared with the proposed LED system of equivalent illumination quality. The results indicate that by retrofitting the HPS luminaires, the energy consumption can be reduced by 60% and with 83.3% reduction in the apparent power. Furthermore, the proposed LED illumination system will significantly improve the power quality, light noise, energy losses, carbon footprint, and operational cost.

高速公路上充足和适当的照明对于安全至关重要。高压钠灯 (HPS) 通常是整个巴基斯坦的标准配置。然而，随着照明技术的进步和能源效率的增长趋势，使用发光二极管灯具 (LED) 改造传统 HPS 灯具正变得越来越流行。低能耗、高显色指数 (CRI)、更长的使用寿命以及相关色温 (CCT) 的多样性使 LED 灯具成为替代低效 HPS 灯的理想选择。用 LED 照明系统改造 HPS 需要资本成本，其可行性取决于节能潜力。本研究展示了在巴基斯坦第二个人口稠密城市 85 公里长的高速公路上安装 4,014 个 HPS 灯具的案例。对 HPS 照明系统进行了有针对性的能源审计，并与同等照明质量的拟议 LED 系统进行了比较。结果表明，通过改造HPS灯具，能耗可降低60%，视在功率降低83.3%。此外，提议的 LED 照明系统将显着改善电能质量、光噪声、能量损失、碳足迹和运营成本。