Assessing real-world emissions from buses and taxis is vital to comprehend their impact on urban air quality. Such vehicles differ significantly from the majority of the fleet owing to their higher mileage rates. However, few studies have focused on specifically assessing the emissions from this segment of the vehicle fleet. In this context, this study evaluated the real-world emissions of nitrogen oxides (NO_x) from in-use buses and taxis in Dublin, Ireland, using crossroad remote sensing technology. The remote sensing system was deployed at strategic locations throughout the city to capture on-road emissions from passing vehicles. The collected data included vehicle related information such as emission standard, make, and mileage, and pollutants including NO_x. Based on this data, analysis was aimed to understand the impact of Euro emission standard, ambient temperature, mileage, and make of the vehicle on NO_x emissions. The results reveal that the average emissions from taxis reduce by 37% from Euro 5 to Euro 6b, and average emissions from Euro 6 buses are 87% lower compared to Euro 5. The trends in emission factors (EFs) of buses and taxis were similar during summer and winter sampling. Moreover, on comparing the emissions from the top five taxi manufacturers, different trends in the emission factors were observed. Finally, the study found that the effect of vehicle mileage on emissions was unclear for both buses and taxis. In any case, these findings provide valuable insights into the real-world emission performance of the existing fleet of buses and taxis in Dublin and highlight the need for targeted measures to reduce emissions from these vehicles. The results can assist policymakers and urban planners in formulating evidence-based strategies to improve air quality in Dublin and other cities facing similar challenges.

Estimating emissions savings from alternative vehicular technologies is essential to streamline urban freight transport policy. We estimate freight emissions in the city of Chennai, India using real-world emission factors obtained from on-board emission measurement systems and trip characteristics collected through an establishment survey. India recently enforced Bharat Stage VI (BS-VI) emission standards and both the central and multiple state governments have introduced battery electric vehicle (BEV) policies. To understand potential benefits, we estimate the emission savings with BS-VI vehicles and BEVs for freight delivery. The BS-VI vehicles reduce tailpipe CO emissions by 20.3%, and HC+NO_x emissions by 74.5%. The GHG emission saving in CO₂ equivalents with BEVs is 50.3%, which increase with a greener energy mix, improved transmission and distribution efficiency, cleaner battery production, and more lifetime vehicle kilometres. BS-VI adoption can deliver significant emission reduction until BEVs and charging infrastructure scale up.