The Polluter Pays Principle (PPP) is fundamental to modern environmental policy, declaring that those responsible for pollution should bear the costs of mitigating its effects. Pyo, Chung, Ma, and Oh (2024) found that awareness of consequences and ascription of responsibility show significant relationships with pro-environmental behavior in firms engaged in sustainable manufacturing. While the PPP is widely implemented in EU policies for industrial pollution and waste management, its application in transport remains inconsistent (Aydin & Esen, 2018). Transport taxation frameworks designed to reduce emissions vary significantly across Europe, with some countries adopting progressive measures, such as emissions-based vehicle taxes, while others lag in implementation. As identified in previous research (Kukjans, 2024), a key barrier to successful implementation is the lack of clear guidelines on transport emissions within supply chains. Many companies focus more on reporting than on actual pollution reduction, often disclosing only a fraction of their Scope 3 emissions and relying on inaccurate methods, such as industry averages or spend-based approaches, which results in significant underreporting. Given that Pope and Owen (2009) calculations suggest that the tradable carbon permits scheme could potentially account for as much as a quarter of the revenue generated by Value Added Tax, this indicates that relying solely on supply chains to improve their reporting is unrealistic, as it would likely require significant additional payments. This paper hypothesizes that comprehensive sustainability reports, including detailed pollution levels and mitigation costs of involved transportation companies, will provide a strong signal for sustainable transport practices and significantly improve transport sustainability. Research Questions: 1) How can transport-related pollution be clearly identified within the supply chain? 2) How can transport pollution levels and the uncovered mitigation costs be effectively measured and allocated to specific segments of the supply chain? 3) Do the improvements identified in Questions 1 and 2 contribute to enhancing overall transport sustainability?