This research delves into sustainability within the road freight transport sector, focusing on how financing policies interact with the capital structures of haulage companies. Employing an agent-based model inspired by Sweden’s freight sector, we simulate strategies for fleet replacement while considering financial health and balance sheets. Hauliers are portrayed as agents with financial attributes sourced from real-world financial statements. Their financing decisions are informed by pecking order theory. Through a series of scenario tests, we simulate the impacts of policy interventions on hauliers’ transition trajectories. Our findings highlight the challenges associated with integrating electric trucks, attributed to limited financing avenues. Both internal and equity financing are found to be inadequate, while debt financing raises concerns about credit risks. These findings remain robust even when incentives like subsidies and reduced interest rates on loans are introduced. The study underscores the intricate interplay between financial factors and sustainable heavy-duty road transport.