NTUA Professor George Yannis has successfully completed his challenge to run 30 Marathons in 30 months in order to actively promote the 30km/h speed limit in cities. He has finished all marathons in under 4 hours. This campaign has a particularly significant social impact, with over 400,000 views and 100,000 visitors per year at the website and social media. It also received wide publicity with dozens of interviews on TV, radio and online media and dozens of articles in newspapers and publications in scientific journals and conferences, with the active support of NTUA and all major International Road Safety and mobility Organizations (ETSC, ECTRI, UITP, POLIS, ERF, IRF, FERSI, FEHRL, ECF, WALK21 and HITE).       George Yannis will continue with the same passion supporting with scientific evidence and promoting slower speeds and safer mobility everywhere and for all.