Like the Holy Grail in the medieval times, the GRAIL system provides a long-sought solution for deploying an intelligent and efficient interaction between vehicles and Vulnerable Road Users (VRUs), namely pedestrians and cyclists. GRAIL stands for GReen Assistant Interfacing Light, aiming at increasing road safety and reassuring VRUs when crossing the street, which is one of the main objectives of the BRAVE EU-funded project. Let’s consider the situation depicted in figure 1, where a couple of pedestrians are standing at the curb on a pedestrian crossing while looking for eye contact with the driver of the oncoming car. Definitely, the couple will not start crossing until they observe some signal indicating that the car is giving way to them.
In order to increase VRUs reassurance, the automated system developed by the University of Alcalá (UAH) performs two actions in parallel that contribute to improving the interaction between the car and the VRUs. On the one hand, the vehicle starts to decrease its speed significantly as soon as those pedestrians are detected by the onboard camera system. On the other hand, the GRAIL system, an array of green diodes located in the front of the vehicle (as shown in figure 2), is turned on.
The combination of both actions, vehicle deceleration and green light coming on, provides a distinct sign to VRUs, indicating that the situation is safe for them to start crossing the street. The operation of the GRAIL system is graphically illustrated in the following video (also available at https://youtu.be/pfDrxVbVcto).
Miguel Ángel SOTELO VÁZQUEZ