At a recent podcast in Lifo, NTUA Professor George Yannis is decoding the new Greek Road Code proposal for 30km/h speed limit in all cities in Greece, the great opportunity for a new safe and sustainable mobility culture. Drawing from extensive European data and simulation studies, he pointed out that city-wide 30km/h speed limit is the since-long waited single road safety measure with such a significant benefit at such a low cost. The myth that lower speed limits significantly delay travel times was refuted by evidence showing only negligible differences and even mid-term traffic improvement. The innovative and impactful NTUA campaign of 30 Marathons in 30 months, implemented by Prof. Yannis, to actively promote the adoption of 30km/h speed limit in all cities worldwide was also highlighted. Full article and related audio-podcast are now available.