SafeWalk: Early Warning System for Pedestrians

Pedestrians on streets are exposed to dangerous situations, particularly when large vehicles cross urban areas and visibility is limited. However, there is a potential way to mitigate these dangers, as sensor technologies are increasingly ubiquitous in vehicles and nearly everyone carries a smartphone.This paper presents a safety application for pedestrians that uses Bluetooth Low Energy (BLE) in smartphones to broadcast Personal Safety Messages (PSMs) with the position, speed and heading of walkers. We started by evaluating the performance of BLE in some smartphone models and obtained very promising results. This technology can provide information even without a direct line of sight between the driver and the pedestrian. Then we developed an Android application with an algorithm for managing the data exchanged between the two parties. The PSMs received by the vehicles are compared with their current location to determine whether a collision will occur, and the driver is warned accordingly. We evaluated in different scenarios, two of which are also used in Euro NCAP tests since 2020. The results are very encouraging because detections were achieved in a timely manner, resulting in a practical early warning system.