Congestion and consolidation: An empirical study of a barge shipping merger

This paper uses consolidation in the barge shipping industry to investigate the efficiencies generated by mergers in congested transportation markets. We study a merger between two barge shipping companies operating on congested transportation routes in the US inland waterway system. Using geographic variation in how the merger impacts traffic volume concentration, we estimate the effects of increased concentration on delays at congested bottlenecks using a novel data set of over one million linked vessel-firm delay observations. The results indicate that the merger decreased delays by 7% on average, suggesting substantial efficiency gains due to increased concentration. These findings have implications for optimal congestion pricing, transportation infrastructure investment, and merger review.