Some road users have been targeted in a way to try and create systems that help increase their safety. We are referring to, in this instance, pedestrians, cyclists and even motorcyclists whom we call Vulnerable Road Users (VRU) due to the fragility they present when compared to other users that circulate on the same roads, in particular cars. These systems fall within the ambit of the Smart Cities that are increasingly growing all over the world. The objective of this dissertation is to take advantage of geofencing technology, i.e., to create a virtual perimeter for a real geographical location in which it is desired to detect at any moment the entrance or exit of an user. To achieve such goals a mobile app was deve loped with the purpose of notifying the user as soon as he enters or exits such geofences. A web-based platform was also conceived and designed for city hall administrators where geofences may be created, updated, deleted and classified. The main focus went towards the creation of geofences in specific points of interest for VRUs, i.e., areas that may be considered dangerous for pedestrians when crossing the road, due to bad visibility for instance, signaling road blocks or construction areas that may cause disruption in traffic or even a road accident.