In modern urban environments, drivers’s visibility can often be limited by obstacles such as parked cars, vegetation, or buildings. These obstructions restrict not only the drivers’ line of sight but also the perception of vehicle safety systems. As a result, the most vulnerable road users — pedestrians, cyclists, motorcyclists, and people with disabilities — often become “invisible” on the road. Even the most advanced autonomous vehicles face challenges in such scenarios: when partial inclusion occurs, the likelihood of failing to detect a pedestrian or cyclist can reach 25–30%. This gap is not merely technical — it can be fatal.
Despite technological progress and awareness campaigns, road accidents remain a heavy burden across Europe, and especially in Greece. In 2024, 19,800 people lost their lives in traffic accidents in Europe, with vulnerable users being disproportionately affected. Two-thirds of these fatalities involved pedestrians, cyclists, or motorcyclists. The European Union has set an ambitious target: to halve the number of deaths and serious injuries by 2030 and to approach zero fatalities by 2050. Until then, each new accident underscores the urgent and ongoing need for safer roads.
This is the challenge that the HIDDEN project (Hybrid Intelligence for Advanced Collective Perception and Decision Making in Complex Urban Environments) seeks to address. Officially launched in July 2025 under the coordination of the I-SENSE research group at the Institute of Communication and Computer Systems (ICCS) of the National Technical University of Athens (NTUA), HIDDEN is funded with nearly €5 million by Horizon Europe and is part of the CCAM (Connected, Cooperative and Automated Mobility) partnership. Bringing together 14 partners and 2 associated entities from 7 EU countries, the project aims to overcome one of the greatest barriers in urban traffic: visual obstructions.
By leveraging cooperative perception, vehicle-to-everything (V2X) technologies, and artificial intelligence, HIDDEN allows vehicles to exchange and interpret data from various sources — other drivers, infrastructure, or even pedestrians — enabling them to “see” beyond the physical limits of their sensors. Its distinguishing feature is the integration of Hybrid Intelligence, a combination of human and machine perception that guides vehicles to make decisions not only with technical precision but also with safety and ethical awareness. As Dr. Angelos Amditis, Project Coordinator and R&D Director at ICCS, explains: “HIDDEN goes beyond conventional AI. We are bringing human judgment to the core of autonomous decisions, so that systems operate with both technical accuracy and ethical responsibility.”
The technologies developed will be tested in real-world conditions as well as in advanced simulators, focusing on high-risk scenarios such as a child running out from behind a parked car, a cyclist navigating mixed traffic, a worker hidden behind dense vegetation, or a vehicle approaching an unsignaled intersection. Greece plays a leading role in this effort, not only coordinating the project but also contributing key technologies through academic and industrial partners. Together, they are shaping the standards and practices that will define the future of autonomous mobility, in Europe and beyond.
Alongside ICCS/NTUA, several Greek companies bring specialized expertise to the HIDDEN project. LIBRA AI Technologies, the project’s technical manager, develops advanced artificial intelligence systems that monitor driver attention and condition, enhancing the safety and intelligence of semi-autonomous vehicles. CIBOS, a spin-off of ICCS/NTUA, focuses on user-centric software development, improving human–machine interfaces and overall driving experience. Meanwhile, SEABILITY INNOVATIONS, responsible for communication and dissemination, ensures broad visibility and societal impact of HIDDEN’s outcomes, promoting the safe integration of autonomous mobility into everyday life.
