Challenges in extending sustainability across a transport supply chain

Sustainability approaches across product supply chains are well-known, while similar knowledge on transport supply chains (TSC) is limited. The purpose of this paper is to explore sustainability approaches and managerial challenges in extending sustainability across a TSC.,This paper presents a case study of a TSC with a shipper, a third-party logistics firm and a hauler. Each actor’s views on sustainability-related communication and relations with other TSC actors are analyzed through the lens of agency theory.,Each dyad in the TSC reveals different, more or less collaboration-based approaches. Challenges are revealed, including the lack of shipper understanding for the TSC context and the use of immature contracts, which disincentivizes sustainability compliance. The multi-tier study object reveals the silencing of distant actors and the need for actors to take on mediating roles to bridge information asymmetries.,Combining literature perspectives (relations, communication and agency theory) provides a deeper understanding of the approaches applied and identifies different challenges. The inclusion of agency theory reveals principal problems such as information asymmetries between agents and less-informed principals and suggests complementary labels of supply chain actors.,Practical contributions include the highlighting of managerial challenges, which can aid managers in extending sustainability across TCSs.,The case study method offers insights into collaboratively improving sustainability in supply chains (such as using contracts), thus having social and environmental implications.,The paper narrows knowledge gaps about managing sustainability among logistics service providers and analyzes data from multi-tier actors.