The transition towards low-emission vehicle technologies, driven largely by efforts to reduce fleet-average CO2 emissions, has led to the widespread introduction of advanced powertrains, including hybridized gasoline vehicles, modern diesel vehicles, and compressed natural gas (CNG) vehicles [1]. While these technologies are primarily promoted for their reduced regulated emissions, their comparative toxicological impacts under realistic driving conditions remain insufficiently understood. This study presents a comparative toxicological assessment of exhaust emissions from five state-of-the-art passenger vehicles representing different propulsion technologies. The vehicles were tested on a chassis dynamometer under controlled laboratory conditions, following a common experimental protocol. The test matrix included gasoline vehicles with varying degrees of hybridization and particulate filtration (with and without gasoline particulate filters, GPF), a diesel vehicle equipped with a diesel particulate filter operated both with and without regeneration, and a dual-fuel vehicle running exclusively on CNG. Exhaust emissions were sampled and used to expose human epithelial cells in vitro using an Air-Liquid Interface exposure system. For each vehicle configuration, cells were exposed for two hours under comparable conditions, enabling a direct comparison of biological responses across technologies and operating modes. A range of toxicological endpoints was assessed to evaluate the cellular effects induced by the different exhaust mixtures. The results show differences in toxicological responses between vehicle technologies and operating conditions. In particular, the diesel vehicle exhibited substantially enhanced biological effects during DPF regeneration compared to non-regenerating operation. Gasoline vehicles displayed technology- and filtration-dependent responses, while the CNG vehicle consistently induced the lowest levels of cellular death among the tested fleet. [1] Fontaras, G., & Samaras, Z. (2010). On the way to 130 g CO2/km-Estimating the future characteristics of the average European passenger car. Energy Policy, 38, 1826-1833.