Abstract
<title>Abstract</title> <p>Although the United Nations Decade of Sustainable Transport began in 2026, carbon dioxide (CO₂) remains the most abundant greenhouse gas in most cities around the world, primarily caused by motor vehicle exhaust emissions. Research has demonstrated that CO₂ monitoring of vehicle fleets requires greater accuracy in the carbon market. Having said that, this study aims to improve the CO₂ monitoring of motor vehicles. A comparative assessment was conducted between the Greenhouse Gas (GHG) Protocol and the Worldwide Harmonized Light-duty Test Procedure (WLTP) and the New European Driving Cycle (NEDC) to evaluate their accuracy and efficiency. In parallel, a 3-in-1 digital platform, the Mobility C3 application, was developed to enable real-time measurement of the distance traveled (km) and the CO₂ emissions of individual vehicles in order to test the above-mentioned methods. The results demonstrated that the NEDC and WLTP methods provide more precise CO₂ measurements, whereas the GHG Protocol demonstrated inaccuracies. These findings have important implications for emission accounting and carbon market mechanisms such as planting trees, protecting forests and trading carbon credits.</p>