Overloaded truck problem in Thailand: Investigating Root Causes, Enforcement Gaps, and Policy Solutions

Thailand’s rapid expansion of its national transportation network has fueled significant growth in the truck freight business, which now accounts for 70% of the country’s freight. However, this growth has also intensified the overloaded truck problem, as businesses seek to reduce costs and gain competitive advantages by exceeding legal weight limits. This study investigates the root causes of truck overloading, focusing on enforcement gaps and policy shortcomings. By analyzing actual truck weight data collected during 2019–2023 through Bridge Weigh-in-Motion (BWIM) technology, which operates covertly beneath bridges, significant discrepancies were found between state weigh station reports and real-world data. These discrepancies are primarily due to weigh station avoidance, often facilitated by bribery. The study highlights how these enforcement gaps weaken law enforcement and hinder effective policy implementation. To address these challenges, the study recommends adopting automated weighing systems, such as BWIM, and introducing an overweight fee permit system. These measures aim to enhance the effectiveness of law enforcement, reduce the potential for corruption, and support sustainable and balanced transport management. The findings provide actionable insights for policymakers and state agencies to develop robust and cost-effective solutions to the overloaded truck problem in Thailand.