The OPEN-3D project opens new horizons for understanding how traffic moves through our cities. By using drones to record traffic scenes from above, the project created rich, easy-to-use datasets that show how thousands of vehicles move across complex road networks. These datasets, freely available to researchers and the public, set new standards for openness, quality, and transparency in urban mobility data. To help others build on this work, the project also released tools and annotated examples that support the development of smarter traffic detection systems using artificial intelligence. Already in use across universities and research labs, these resources are expected to inspire new ideas for safer, more efficient transport. OPEN-3D demonstrates how sharing data openly can fuel innovation and help cities respond to the growing challenges of mobility.