Purpose - Transportation is a non-value-added process, and organizations constantly need to improve their processes to become more efficient, and sustainable to remain competitive. Thus, the study’s purpose is:

To investigate how semi-internal milk runs should be organized to improve efficiency

To answer the purpose, two investigation questions were established:

[1] How is a semi-internal milk run organized?[2] Which potentials exist when utilizing a semi-internal milk run?

Method – The study is a case study designed after an early review of the flow of milk runs. The data collection techniques used to answer the questions were observation, observation protocols, and interviews. Throughout the study, the focus is to investigate the organization and then understand and describe the improvements. Each data collection is explained and described based on how these improve or impair the study's validity. The results of the method are then compared with the collected theory, which provides answers to the questions.

Results – Previous research clearly shows how companies should apply milk runs for increased efficiency. Transport improvement has not been a focal point for either industrial operations or transport logistics. Milk runs are explored and described but the subject of semi-internal milk runs is not researched. This means that companies today have organized milk runs based on specific needs for the individual business. The study shows that logistics systems, communication, information, and continuous improvement are important parts to make a milk runs more efficient, which can also be applied to semi-internal milk run. Finally, flexibility in semi-internal milk runs is considered important in terms of time, quantity, and location to be efficient. Efficiency is achieved through a well-executed value stream analysis, which can then identify various transport wastes that are the basis for further development of semi-internal transport.

Implications – The study's conclusions and results can be used by similar companies to map semi-internal milk runs and thought mapping develop and streamline. The study also shows that Lean needs to be worked on continuously.

Limitations – This study was conducted based on a single case study. The results are relevant if other businesses with similar conditions perceive them to be applicable to their operations. The number of research milk runs and the impact of the business's other processes on milk runs were not examined in-depth, which limits the result to describe the organization of semi-internal milk runs.

Keywords – semi-internal milk runs, milk runs, efficiency, Lean.