The Cost of Traffic Congestion and Marginal Cost of Delay in Bangkok Metropolis

Traffic congestion in Bangkok, particularly during rush hours, imposes significant private and external economic costs on society, a problem exacerbated by the rapid increase in the number of private vehicles in the city. To the best of our knowledge, no study has estimated the cost of traffic congestion in Thailand using a survey research design. This study aims to estimate both the cost and the marginal cost of heavy traffic during rush hours, utilizing data gathered from 215 commuters in Bangkok and nearby suburbs. The findings indicate that the annual traffic congestion costs per vehicle range between THB 77,021 and THB 76,155 (USD 2,567 and USD 2,538) at 2023 price levels, depending on the greenhouse gas (GHG) damage cost discount rates used. Additionally, the marginal cost of delay per vehicle due to heavy traffic is approximately THB 646 (USD 22) at 2023 price levels. This value can serve as a proxy for the benefit (or avoided cost) that commuters could gain if the government were to implement traffic congestion mitigation measures, such as congestion charges. While imposing fees could be one potential solution to address the traffic problem in Bangkok, further research is needed to determine the appropriate amount of charges, considering factors like the price elasticity of demand for congestion charges and their acceptability to the public.