This paper investigates investments in public–private partnerships within the transport sector and their impact on CO₂ emissions from transportation in the East Asian and Pacific regions. It explores the relationships between CO₂ emissions from transportation, investment in public–private partnerships, renewable energy, research and development, and economic growth. The study employs a unit root test, a cointegration model, and a vector autoregressive model, covering the period from 1990 to 2023. The findings suggest that public–private partnerships in the transport sector can reduce CO₂ emissions through adequate investment. Furthermore, renewable energy diminishes CO₂ emissions by regulating them and concurrently producing fewer emissions. Environmental research and development help reduce CO₂ emissions in the transport sector, while economic growth contributes to an increase in transport sector CO₂ emissions. These findings provide critical insights for policymakers, underscoring the necessity for a systematic reallocation of public–private partnership investments in the transport sector to reduce CO₂ emissions and enhance environmental sustainability in East Asian and Pacific regions.