Abstract: A method of alerting a user of a mobile communication device having a processor about a risk arising from proximate drivers or pedestrians. The method comprises receiving a list of a plurality of proximate mobile communication devices from a central unit via a network, establishing a peer to peer (P2P) connection with each the proximate mobile communication device, acquiring positioning data from each the proximate mobile communication device via a respective the P2P connection, locally using the processor for calculating at least one potential collision course with at least one of the plurality of proximate mobile communication devices according to the positioning data, and locally presenting an alert indicative of a risk to the user according to the at least one potential collision course.