A Model for Describing the Hydrodynamics of Crowds (image) CNRS Share Print E-Mail Caption Image A: Image of the starting area for the 2016 Bank of America Chicago Marathon. Image B: Zoom on the area framed by A, showing the movement sequence of the race organizers (yellow vests) as they guide runners toward the starting area, thereby inducing speed and density disruptions that spread at a constant speed through the crowd. Image C: Speed and density waves in the same crowd, spreading in the opposite direction as the crowd's movement. Credit © Nicolas Bain/Science Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.