Assessment of Lean Scheduling in Road Infrastructure Projects based on Last Planner System: Empirical Evidence from Urban Roads in Addis Ababa

抄録

The construction industry, particularly road construction, frequently suffers from schedule delays, cost overruns, and workflow inefficiencies. Traditional scheduling approaches reliant on static critical path methods have been found to be inadequate in fully managing the inherent variability and uncertainity of road construction and maintenance operations. In contrast, the Last Planner System, a key component of lean construction, promotes collaborative planning, constraint management, and continuous workflow improvement, offering a dynamic framework for enhancing project reliability and control. This research aims to assess the effectiveness of lean scheduling using the Last Planner System for under-construction and maintenance road projects. By leveraging empirical data from ongoing projects, the study evaluates the planning reliability, workflow efficiency, and scheduling performance using metrics such as Percent Plan Completed and Coefficient of Variance. The results revealed that maintenance projects showed greater fluctuation in Percent Plan Completed than underconstruction projects, underscoring the need for adaptive scheduling. This research offers practical insights for contractors, project managers, and public agencies aiming to optimize planning reliability, reduce waste, and improve infrastructure delivery.