The International Cycling Safety Conference (ICSC2020) organised with great success a webinar titled “Single bicycle crashes as a rising problem” which was held online at November 5th 2020. The large majority of serious injuries among cyclists are due to single crashes and in a few countries the same applies to cyclist deaths. This special session highlights the size of the problem, trends, existing data and knowledge and provide a discussion about why so little is known about causes and measures to address single-bicycle crashes.