Optimizing the schedule of dispatching RMC trucks through genetic algorithms

Effectively and efficiently delivering Ready Mixed Concrete (RMC) to construction sites is an important issue to the RMC batch plant manager. The RMC batch plant manager has to consider both timeliness and flexibility to develop an efficient schedule of dispatching RMC trucks, which balances the operations at the construction sites and the batch plant. The requests of RMC deliveries from different construction sites usually swamp into the batch plant at certain working hours. As a result, the batch plant manager has to quickly decide a dispatching schedule that can satisfy the needs from different construction sites. The existing dispatching schedule mainly depends on the experiences and preferences of the dispatcher. For example, the RMC plant manager may dispatch as many RMC trucks as possible to the busiest construction site. However, such an approach might result in the RMC trucks line up at the busiest job site while keeping other construction sites waiting for the arrivals of RMC trucks. A systematic approach to such a problem has seldom been taken due to the complexity and uncertainty involved within the dispatching process. Therefore, there is a need to develop a systematic model that optimizes the schedule of dispatching RMC trucks. This paper first analyzes the factors that impact the RMC delivery process, then builds a model based on Genetic Algorithms and the simulation technique to find the best dispatching schedule which minimizes the total waiting duration of RMC trucks at construction sites and satisfies the needs of RMC deliveries from different construction sites. In addition, a user-friendly computer program is built to help the batch plant manager streamline the dispatching process. Results show that this new systematic model along with the implemented computer program can quickly generate efficient and flexible solutions to dispatching RMC trucks. (C) 2004 Elsevier B.V. All rights reserved.