Felix Leach is an Associate Professor of Engineering Science at the University of Oxford, in addition to Director of Studies, Fellow and Tutor in Engineering Science at Keble College. Felix has published over 70 peer-reviewed research papers, and has spent over a decade working in close collaboration with industry using world-leading measurement capabilities to help develop a clean engine. His work engages with public policy on vehicle emissions and air quality, involving projects with the Oxford Bus Company and local councils. Felix holds MEng and DPhil degrees in engineering science from the University of Oxford and is a Chartered Engineer and Member of the Institution of Mechanical Engineers, a Fellow of the Higher Education Academy, and a member of SAE. Felix has been fortunate enough to be the recipient of many awards, including for his first book Racing Toward Zero, co-authored with Kelly Senecal, published by SAE International. Nick Molden is Founder and Chief Executive Officer of Emissions Analytics Ltd, a company he set up in 2011 to specialize in the measurement of real-world emissions from vehicles. The company pioneered the development of on-road test methodologies, including the launch of the EQUA Index in 2016. He has published many peer-reviewed academic papers, collaborates with universities around the world, presents regularly at industry conferences, and acts as an expert witness in court cases internationally. Nick is a Founder and Director of the AIR Alliance, a not-for-profit organization that publishes free public ratings for the real-world emissions and interior air quality of vehicles. He is chairman of two standardization groups within the Comité Européen de Normalisation: CEN Workshop 90 on urban tailpipe nitrogen oxide emissions, and CEN Workshop 103 on pollution ingress into vehicle interiors. Nick holds an MA in Philosophy, Politics & Economics from the University of Oxford. He is also an Honorary Senior Research Fellow at Imperial College London.