On the 24th November, 2021 the Sixth International Workshop on Data Science (IWDS 2021) was held in Zagreb, Croatia. It was organized by the Centre of Research Excellence for Data Science and Advanced Cooperative Systems, Research unit Data Science and the project Advanced methods and technologies in Data Science and Cooperative Systems (DATACROSS). The workshop aimed to foster the interaction of researchers and exchange new ideas in the diverse area of data science and encourage interaction and networking between data science researchers and practitioners from both industry and government organizations. Assoc. prof. Edouard Ivanjko participated with the poster titled “Agent-based Urban Traffic Control” presenting the work done in cooperation with young researchers postdoc Martin Gregurić, Ph.D., Dino Čakija, Krešimir Kušić, Mladen Miletić and Filip Vrbanić related to applying reinforcement learning to control traffic flows in urban environments. He also contributed to the poster presentation “Motorway Bottleneck Detection Using Speed Transition Matrices” given by young researcher Leo Tišljarić to present the results achieved by researchers Leo Tišljarić, Filip Vrbanić, Edouard Ivanjko, and Tonči Carić. We all congratulate on the successful presentation.